From a94fa2f70cea185050fdbcd7bd8266da05b75a35 Mon Sep 17 00:00:00 2001
From: github-actions <github-actions@github.com>
Date: Wed, 4 Aug 2021 10:24:15 +0000
Subject: [PATCH] Deployed 70332ec with MkDocs version: 1.1.2

---
 404.html                                      | 161 +++++++++--------
 CODE_OF_CONDUCT/index.html                    | 161 +++++++++--------
 CONTRIBUTING/index.html                       | 161 +++++++++--------
 big_data/evolution/index.html                 | 167 ++++++++++--------
 big_data/intro/index.html                     | 167 ++++++++++--------
 big_data/tasks/index.html                     | 167 ++++++++++--------
 databases_nosql/further_reading/index.html    | 167 ++++++++++--------
 databases_nosql/intro/index.html              | 167 ++++++++++--------
 databases_nosql/key_concepts/index.html       | 167 ++++++++++--------
 databases_sql/backup_recovery/index.html      | 167 ++++++++++--------
 databases_sql/concepts/index.html             | 167 ++++++++++--------
 databases_sql/conclusion/index.html           | 167 ++++++++++--------
 databases_sql/innodb/index.html               | 167 ++++++++++--------
 databases_sql/intro/index.html                | 167 ++++++++++--------
 databases_sql/lab/index.html                  | 167 ++++++++++--------
 databases_sql/mysql/index.html                | 167 ++++++++++--------
 databases_sql/operations/index.html           | 161 +++++++++--------
 databases_sql/query_performance/index.html    | 167 ++++++++++--------
 databases_sql/replication/index.html          | 167 ++++++++++--------
 databases_sql/select_query/index.html         | 167 ++++++++++--------
 git/branches/index.html                       | 165 +++++++++--------
 git/conclusion/index.html                     | 165 +++++++++--------
 git/git-basics/index.html                     | 165 +++++++++--------
 git/github-hooks/index.html                   | 165 +++++++++--------
 index.html                                    | 161 +++++++++--------
 linux_basics/command_line_basics/index.html   | 163 +++++++++--------
 linux_basics/conclusion/index.html            | 163 +++++++++--------
 linux_basics/intro/index.html                 | 163 +++++++++--------
 .../linux_server_administration/index.html    | 163 +++++++++--------
 linux_networking/conclusion/index.html        | 165 +++++++++--------
 linux_networking/dns/index.html               | 165 +++++++++--------
 linux_networking/http/index.html              | 165 +++++++++--------
 linux_networking/intro/index.html             | 165 +++++++++--------
 linux_networking/ipr/index.html               | 165 +++++++++--------
 linux_networking/tcp/index.html               | 165 +++++++++--------
 linux_networking/udp/index.html               | 165 +++++++++--------
 metrics_and_monitoring/alerts/index.html      | 167 ++++++++++--------
 .../best_practices/index.html                 | 167 ++++++++++--------
 .../command-line_tools/index.html             | 167 ++++++++++--------
 metrics_and_monitoring/conclusion/index.html  | 167 ++++++++++--------
 .../introduction/index.html                   | 167 ++++++++++--------
 .../observability/index.html                  | 167 ++++++++++--------
 .../third-party_monitoring/index.html         | 167 ++++++++++--------
 python_web/intro/index.html                   | 167 ++++++++++--------
 python_web/python-concepts/index.html         | 167 ++++++++++--------
 python_web/python-web-flask/index.html        | 167 ++++++++++--------
 python_web/sre-conclusion/index.html          | 167 ++++++++++--------
 python_web/url-shorten-app/index.html         | 167 ++++++++++--------
 security/conclusion/index.html                | 167 ++++++++++--------
 security/fundamentals/index.html              | 167 ++++++++++--------
 security/intro/index.html                     | 167 ++++++++++--------
 security/network_security/index.html          | 167 ++++++++++--------
 security/threats_attacks_defences/index.html  | 167 ++++++++++--------
 security/writing_secure_code/index.html       | 167 ++++++++++--------
 sitemap.xml                                   | 116 ++++++------
 sitemap.xml.gz                                | Bin 223 -> 224 bytes
 sre_community/index.html                      | 161 +++++++++--------
 systems_design/availability/index.html        | 167 ++++++++++--------
 systems_design/conclusion/index.html          | 167 ++++++++++--------
 systems_design/fault-tolerance/index.html     | 167 ++++++++++--------
 systems_design/intro/index.html               | 167 ++++++++++--------
 systems_design/scalability/index.html         | 167 ++++++++++--------
 62 files changed, 5475 insertions(+), 4587 deletions(-)

diff --git a/404.html b/404.html
index e8bfba5..c6e6c33 100644
--- a/404.html
+++ b/404.html
@@ -179,13 +179,13 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -201,11 +201,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -274,14 +296,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -350,14 +372,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -459,11 +481,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -471,14 +490,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -550,11 +569,8 @@
     </li>
   
 
-    
-      
-      
-      
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+          
+            
   
   
   
@@ -562,14 +578,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
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@@ -584,14 +600,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -678,14 +694,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -760,14 +776,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -824,14 +840,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -885,11 +901,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -897,14 +910,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -976,11 +989,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -988,14 +998,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1091,11 +1101,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1103,14 +1110,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1194,6 +1201,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/CODE_OF_CONDUCT/index.html b/CODE_OF_CONDUCT/index.html
index 2ffd2c8..4be8195 100644
--- a/CODE_OF_CONDUCT/index.html
+++ b/CODE_OF_CONDUCT/index.html
@@ -184,13 +184,13 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
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           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +206,33 @@
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       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +301,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
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@@ -355,14 +377,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +486,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +495,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +574,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -567,14 +583,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -589,14 +605,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -683,14 +699,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -765,14 +781,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -829,14 +845,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -890,11 +906,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -902,14 +915,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -981,11 +994,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -993,14 +1003,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1096,11 +1106,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1108,14 +1115,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1199,6 +1206,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/CONTRIBUTING/index.html b/CONTRIBUTING/index.html
index 1c714b6..f0bb26a 100644
--- a/CONTRIBUTING/index.html
+++ b/CONTRIBUTING/index.html
@@ -184,13 +184,13 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +206,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +301,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +377,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +486,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +495,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +574,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -567,14 +583,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -589,14 +605,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -683,14 +699,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -765,14 +781,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -829,14 +845,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -890,11 +906,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -902,14 +915,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -981,11 +994,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -993,14 +1003,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1096,11 +1106,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1108,14 +1115,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1199,6 +1206,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/big_data/evolution/index.html b/big_data/evolution/index.html
index d046aeb..aa6540e 100644
--- a/big_data/evolution/index.html
+++ b/big_data/evolution/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -569,14 +587,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" checked>
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -591,14 +609,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -685,14 +703,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -767,14 +785,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -833,14 +851,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" checked>
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -903,11 +921,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -915,14 +930,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -994,11 +1009,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1006,14 +1018,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1109,11 +1121,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1121,14 +1130,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1212,6 +1221,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/big_data/intro/index.html b/big_data/intro/index.html
index 4e182f4..61657e5 100644
--- a/big_data/intro/index.html
+++ b/big_data/intro/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -569,14 +587,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" checked>
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -591,14 +609,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -685,14 +703,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -767,14 +785,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -833,14 +851,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" checked>
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -953,11 +971,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -965,14 +980,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1044,11 +1059,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1056,14 +1068,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1159,11 +1171,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1171,14 +1180,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1262,6 +1271,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/big_data/tasks/index.html b/big_data/tasks/index.html
index 30f0c2a..75af601 100644
--- a/big_data/tasks/index.html
+++ b/big_data/tasks/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -569,14 +587,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" checked>
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -591,14 +609,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -685,14 +703,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -767,14 +785,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -833,14 +851,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" checked>
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -939,11 +957,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -951,14 +966,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1030,11 +1045,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1042,14 +1054,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1145,11 +1157,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1157,14 +1166,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1248,6 +1257,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/databases_nosql/further_reading/index.html b/databases_nosql/further_reading/index.html
index 6af3076..73f13b4 100644
--- a/databases_nosql/further_reading/index.html
+++ b/databases_nosql/further_reading/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -569,14 +587,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" checked>
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
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         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
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@@ -591,14 +609,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
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       </label>
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+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
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@@ -685,14 +703,14 @@
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-      <label class="md-nav__link" for="nav-4-1-7">
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         Operational Concepts
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       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" checked>
       
-      <label class="md-nav__link" for="nav-4-2">
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         NoSQL
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       </label>
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-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
           NoSQL
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
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-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -903,11 +921,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -915,14 +930,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
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       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
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           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -994,11 +1009,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1006,14 +1018,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
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       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1109,11 +1121,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1121,14 +1130,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
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       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1212,6 +1221,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/databases_nosql/intro/index.html b/databases_nosql/intro/index.html
index bea459f..68319ee 100644
--- a/databases_nosql/intro/index.html
+++ b/databases_nosql/intro/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
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@@ -206,11 +208,33 @@
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       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
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@@ -279,14 +303,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
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@@ -355,14 +379,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
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       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
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-      <label class="md-nav__link" for="nav-3">
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       </label>
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-        <label class="md-nav__title" for="nav-3">
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           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
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-    
-      
-      
-      
-
+          
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@@ -569,14 +587,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" checked>
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
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           Data
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
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-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
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       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
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+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
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           Relational Databases
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@@ -685,14 +703,14 @@
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-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
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       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
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+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
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           Operational Concepts
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@@ -769,14 +787,14 @@
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+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" checked>
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
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@@ -933,14 +951,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -994,11 +1012,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1006,14 +1021,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
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           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1085,11 +1100,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1097,14 +1109,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1200,11 +1212,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1212,14 +1221,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
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       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1303,6 +1312,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/databases_nosql/key_concepts/index.html b/databases_nosql/key_concepts/index.html
index fcf5f52..2b60219 100644
--- a/databases_nosql/key_concepts/index.html
+++ b/databases_nosql/key_concepts/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
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         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
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           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
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@@ -206,11 +208,33 @@
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       <label class="md-nav__link" for="nav-2-1">
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+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
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+          
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+  
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       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
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+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
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@@ -279,14 +303,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -569,14 +587,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" checked>
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -591,14 +609,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -685,14 +703,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -769,14 +787,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" checked>
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -912,14 +930,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -973,11 +991,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -985,14 +1000,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1064,11 +1079,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1076,14 +1088,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1179,11 +1191,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1191,14 +1200,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1282,6 +1291,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/databases_sql/backup_recovery/index.html b/databases_sql/backup_recovery/index.html
index 7da65da..870c61e 100644
--- a/databases_sql/backup_recovery/index.html
+++ b/databases_sql/backup_recovery/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
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         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
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@@ -206,11 +208,33 @@
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       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
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+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
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+          
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+  
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+    
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+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
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@@ -279,14 +303,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
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         <span class="md-nav__icon md-icon"></span>
       </label>
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-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
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@@ -355,14 +379,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
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         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
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+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
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-      <label class="md-nav__link" for="nav-3">
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         <span class="md-nav__icon md-icon"></span>
       </label>
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           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
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@@ -569,14 +587,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" checked>
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+      <label class="md-nav__link" for="nav-2-3">
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@@ -593,14 +611,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" checked>
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
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       </label>
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+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
           Relational Databases
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@@ -748,14 +766,14 @@
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-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
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         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
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@@ -830,14 +848,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
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         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
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           <span class="md-nav__icon md-icon"></span>
           NoSQL
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@@ -894,14 +912,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
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         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
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+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -955,11 +973,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -967,14 +982,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
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       </label>
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+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
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           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1046,11 +1061,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1058,14 +1070,14 @@
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+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
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           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1161,11 +1173,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1173,14 +1182,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
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       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1264,6 +1273,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/databases_sql/concepts/index.html b/databases_sql/concepts/index.html
index dfe8399..1290cb3 100644
--- a/databases_sql/concepts/index.html
+++ b/databases_sql/concepts/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
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           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
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@@ -206,11 +208,33 @@
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       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
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+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
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@@ -279,14 +303,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
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@@ -355,14 +379,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
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-      <label class="md-nav__link" for="nav-3">
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       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
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           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -569,14 +587,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" checked>
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
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           <span class="md-nav__icon md-icon"></span>
           Data
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@@ -593,14 +611,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" checked>
       
-      <label class="md-nav__link" for="nav-4-1">
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         Relational Databases
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       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
           Relational Databases
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
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-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
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@@ -867,14 +885,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -928,11 +946,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -940,14 +955,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
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       </label>
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-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
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           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1019,11 +1034,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1031,14 +1043,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
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+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1134,11 +1146,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1146,14 +1155,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
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       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
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           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1237,6 +1246,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/databases_sql/conclusion/index.html b/databases_sql/conclusion/index.html
index 1c2171a..b80aede 100644
--- a/databases_sql/conclusion/index.html
+++ b/databases_sql/conclusion/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
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           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
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@@ -206,11 +208,33 @@
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       <label class="md-nav__link" for="nav-2-1">
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+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
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+          Fundamentals Series
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+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
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       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
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@@ -279,14 +303,14 @@
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-      <label class="md-nav__link" for="nav-2-2">
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       </label>
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           <span class="md-nav__icon md-icon"></span>
           Git
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@@ -355,14 +379,14 @@
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-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
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       </label>
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           Linux Networking
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@@ -464,11 +488,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
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-      <label class="md-nav__link" for="nav-3">
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@@ -555,11 +576,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -569,14 +587,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" checked>
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-      <label class="md-nav__link" for="nav-4">
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@@ -593,14 +611,14 @@
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+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
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-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
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       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
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+        <label class="md-nav__title" for="nav-2-3-1-7">
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
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-      <label class="md-nav__link" for="nav-4-2">
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       </label>
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-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
           NoSQL
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
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       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -932,11 +950,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -944,14 +959,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
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-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1023,11 +1038,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1035,14 +1047,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
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       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1138,11 +1150,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1150,14 +1159,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
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       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1241,6 +1250,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/databases_sql/innodb/index.html b/databases_sql/innodb/index.html
index 796c3da..74d8e1d 100644
--- a/databases_sql/innodb/index.html
+++ b/databases_sql/innodb/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
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         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
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           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
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@@ -206,11 +208,33 @@
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       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
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+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
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@@ -279,14 +303,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
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       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
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@@ -355,14 +379,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
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       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
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+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
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-    
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-      
-      
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+          
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@@ -476,14 +497,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
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       </label>
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           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
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@@ -569,14 +587,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" checked>
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
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           <span class="md-nav__icon md-icon"></span>
           Data
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+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" checked>
       
-      <label class="md-nav__link" for="nav-4-1">
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       </label>
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+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
           Relational Databases
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-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
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+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
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+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
           NoSQL
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@@ -881,14 +899,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -942,11 +960,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -954,14 +969,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1033,11 +1048,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1045,14 +1057,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
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       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
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+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
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           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1148,11 +1160,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1160,14 +1169,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
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-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
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           <span class="md-nav__icon md-icon"></span>
           Security
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@@ -1251,6 +1260,12 @@
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+          
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+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/databases_sql/intro/index.html b/databases_sql/intro/index.html
index f3a9bf0..2e7fd83 100644
--- a/databases_sql/intro/index.html
+++ b/databases_sql/intro/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
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           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
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@@ -206,11 +208,33 @@
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       <label class="md-nav__link" for="nav-2-1">
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+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
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+          
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       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
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+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
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@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -569,14 +587,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" checked>
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -593,14 +611,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" checked>
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -760,14 +778,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -842,14 +860,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -906,14 +924,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -967,11 +985,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -979,14 +994,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1058,11 +1073,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1070,14 +1082,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1173,11 +1185,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1185,14 +1194,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1276,6 +1285,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/databases_sql/lab/index.html b/databases_sql/lab/index.html
index 30d1b57..2ea0791 100644
--- a/databases_sql/lab/index.html
+++ b/databases_sql/lab/index.html
@@ -171,21 +171,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -201,11 +203,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -274,14 +298,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -350,14 +374,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -459,11 +483,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -471,14 +492,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -550,11 +571,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -564,14 +582,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" checked>
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -588,14 +606,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" checked>
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -682,14 +700,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -771,14 +789,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -835,14 +853,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -896,11 +914,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -908,14 +923,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -987,11 +1002,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -999,14 +1011,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1102,11 +1114,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1114,14 +1123,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1205,6 +1214,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/databases_sql/mysql/index.html b/databases_sql/mysql/index.html
index 911d757..bcc9f1c 100644
--- a/databases_sql/mysql/index.html
+++ b/databases_sql/mysql/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
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           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
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@@ -206,11 +208,33 @@
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       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
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+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
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@@ -355,14 +379,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
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           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -569,14 +587,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" checked>
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
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           <span class="md-nav__icon md-icon"></span>
           Data
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@@ -593,14 +611,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" checked>
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
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@@ -721,14 +739,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
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@@ -803,14 +821,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
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@@ -867,14 +885,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -928,11 +946,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -940,14 +955,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
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       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1019,11 +1034,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1031,14 +1043,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
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       </label>
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-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1134,11 +1146,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1146,14 +1155,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
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       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1237,6 +1246,12 @@
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+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/databases_sql/operations/index.html b/databases_sql/operations/index.html
index 84d7319..a3d3ab4 100644
--- a/databases_sql/operations/index.html
+++ b/databases_sql/operations/index.html
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       <label class="md-nav__link" for="nav-2">
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         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
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           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
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@@ -201,11 +201,33 @@
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       <label class="md-nav__link" for="nav-2-1">
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+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
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+          Fundamentals Series
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+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
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       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
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@@ -274,14 +296,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
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-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
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-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
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@@ -350,14 +372,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -459,11 +481,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -471,14 +490,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
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-      <label class="md-nav__link" for="nav-3">
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       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
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           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -550,11 +569,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -562,14 +578,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
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         <span class="md-nav__icon md-icon"></span>
       </label>
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+      <nav class="md-nav" aria-label="Data" data-md-level="2">
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+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
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       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
           Big Data
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@@ -885,11 +901,8 @@
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-    
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-      
-      
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+          
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@@ -976,11 +989,8 @@
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           Metrics and Monitoring
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@@ -1091,11 +1101,8 @@
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-    
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-      
-      
-
+          
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@@ -1103,14 +1110,14 @@
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           Security
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@@ -1194,6 +1201,12 @@
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+          
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+  
+
     
       
       
diff --git a/databases_sql/query_performance/index.html b/databases_sql/query_performance/index.html
index 49a0a4f..f0c2a13 100644
--- a/databases_sql/query_performance/index.html
+++ b/databases_sql/query_performance/index.html
@@ -176,21 +176,23 @@
 
   
   
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       <label class="md-nav__link" for="nav-2-1">
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+      
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         Linux Basics
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       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
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@@ -464,11 +488,8 @@
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@@ -555,11 +576,8 @@
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-      <label class="md-nav__link" for="nav-4-3">
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           Big Data
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@@ -957,11 +975,8 @@
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-    
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@@ -969,14 +984,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
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@@ -1048,11 +1063,8 @@
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-    
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@@ -1163,11 +1175,8 @@
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-    
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+          
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
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@@ -1266,6 +1275,12 @@
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+          
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diff --git a/databases_sql/replication/index.html b/databases_sql/replication/index.html
index a182ae0..c3e492f 100644
--- a/databases_sql/replication/index.html
+++ b/databases_sql/replication/index.html
@@ -176,21 +176,23 @@
 
   
   
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       <label class="md-nav__link" for="nav-2-1">
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@@ -464,11 +488,8 @@
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-    
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@@ -555,11 +576,8 @@
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-    
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-      
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           Big Data
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@@ -948,11 +966,8 @@
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-    
-      
-      
-      
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+          
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@@ -960,14 +975,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
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@@ -1039,11 +1054,8 @@
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-    
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@@ -1154,11 +1166,8 @@
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-    
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@@ -1257,6 +1266,12 @@
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+          
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+  
+
     
       
       
diff --git a/databases_sql/select_query/index.html b/databases_sql/select_query/index.html
index 1a0d7db..37f5dbe 100644
--- a/databases_sql/select_query/index.html
+++ b/databases_sql/select_query/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
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@@ -464,11 +488,8 @@
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@@ -476,14 +497,14 @@
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@@ -555,11 +576,8 @@
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-    
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+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1156,11 +1168,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1168,14 +1177,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1259,6 +1268,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/git/branches/index.html b/git/branches/index.html
index b7cf123..a507f58 100644
--- a/git/branches/index.html
+++ b/git/branches/index.html
@@ -186,11 +186,35 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
+        Level 101
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
+        <label class="md-nav__title" for="nav-2">
+          <span class="md-nav__icon md-icon"></span>
+          Level 101
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+    
+  
+  
+    
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" checked>
+      
+      <label class="md-nav__link" for="nav-2-1">
         Fundamentals Series
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
-        <label class="md-nav__title" for="nav-2">
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
           <span class="md-nav__icon md-icon"></span>
           Fundamentals Series
         </label>
@@ -205,14 +229,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
       
-      <label class="md-nav__link" for="nav-2-1">
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -283,14 +307,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" checked>
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -397,14 +421,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -506,11 +530,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -518,14 +539,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -597,11 +618,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -609,14 +627,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -631,14 +649,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -725,14 +743,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -807,14 +825,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -871,14 +889,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -932,11 +950,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -944,14 +959,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1023,11 +1038,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1035,14 +1047,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1138,11 +1150,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1150,14 +1159,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1241,6 +1250,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/git/conclusion/index.html b/git/conclusion/index.html
index 5002e5c..a75b6fc 100644
--- a/git/conclusion/index.html
+++ b/git/conclusion/index.html
@@ -186,11 +186,35 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
+        Level 101
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
+        <label class="md-nav__title" for="nav-2">
+          <span class="md-nav__icon md-icon"></span>
+          Level 101
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+    
+  
+  
+    
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" checked>
+      
+      <label class="md-nav__link" for="nav-2-1">
         Fundamentals Series
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
-        <label class="md-nav__title" for="nav-2">
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
           <span class="md-nav__icon md-icon"></span>
           Fundamentals Series
         </label>
@@ -205,14 +229,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
       
-      <label class="md-nav__link" for="nav-2-1">
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -283,14 +307,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" checked>
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -393,14 +417,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -502,11 +526,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -514,14 +535,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -593,11 +614,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -605,14 +623,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -627,14 +645,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -721,14 +739,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -803,14 +821,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -867,14 +885,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -928,11 +946,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -940,14 +955,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1019,11 +1034,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1031,14 +1043,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1134,11 +1146,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1146,14 +1155,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1237,6 +1246,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/git/git-basics/index.html b/git/git-basics/index.html
index d4f1954..634527c 100644
--- a/git/git-basics/index.html
+++ b/git/git-basics/index.html
@@ -186,11 +186,35 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
+        Level 101
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
+        <label class="md-nav__title" for="nav-2">
+          <span class="md-nav__icon md-icon"></span>
+          Level 101
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+    
+  
+  
+    
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" checked>
+      
+      <label class="md-nav__link" for="nav-2-1">
         Fundamentals Series
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
-        <label class="md-nav__title" for="nav-2">
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
           <span class="md-nav__icon md-icon"></span>
           Fundamentals Series
         </label>
@@ -205,14 +229,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
       
-      <label class="md-nav__link" for="nav-2-1">
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -283,14 +307,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" checked>
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -494,14 +518,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -603,11 +627,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -615,14 +636,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -694,11 +715,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -706,14 +724,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -728,14 +746,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -822,14 +840,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -904,14 +922,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -968,14 +986,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -1029,11 +1047,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1041,14 +1056,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1120,11 +1135,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1132,14 +1144,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1235,11 +1247,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1247,14 +1256,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1338,6 +1347,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/git/github-hooks/index.html b/git/github-hooks/index.html
index eef9063..6e1527c 100644
--- a/git/github-hooks/index.html
+++ b/git/github-hooks/index.html
@@ -186,11 +186,35 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
+        Level 101
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
+        <label class="md-nav__title" for="nav-2">
+          <span class="md-nav__icon md-icon"></span>
+          Level 101
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+    
+  
+  
+    
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" checked>
+      
+      <label class="md-nav__link" for="nav-2-1">
         Fundamentals Series
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
-        <label class="md-nav__title" for="nav-2">
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
           <span class="md-nav__icon md-icon"></span>
           Fundamentals Series
         </label>
@@ -205,14 +229,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
       
-      <label class="md-nav__link" for="nav-2-1">
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -283,14 +307,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" checked>
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -397,14 +421,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -506,11 +530,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -518,14 +539,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -597,11 +618,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -609,14 +627,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -631,14 +649,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -725,14 +743,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -807,14 +825,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -871,14 +889,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -932,11 +950,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -944,14 +959,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1023,11 +1038,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1035,14 +1047,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1138,11 +1150,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1150,14 +1159,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1241,6 +1250,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/index.html b/index.html
index 7d760de..40b8de3 100644
--- a/index.html
+++ b/index.html
@@ -193,13 +193,13 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -215,11 +215,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -288,14 +310,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -364,14 +386,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -473,11 +495,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -485,14 +504,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -564,11 +583,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -576,14 +592,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -598,14 +614,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -692,14 +708,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -774,14 +790,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -838,14 +854,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -899,11 +915,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -911,14 +924,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -990,11 +1003,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1002,14 +1012,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1105,11 +1115,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1117,14 +1124,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
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index 6663955..e0efee4 100644
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diff --git a/linux_basics/conclusion/index.html b/linux_basics/conclusion/index.html
index 6f83601..fc0f585 100644
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           <span class="md-nav__icon md-icon"></span>
           Big Data
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@@ -939,11 +957,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -951,14 +966,14 @@
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-      <label class="md-nav__link" for="nav-5">
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           Systems Design
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@@ -1030,11 +1045,8 @@
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-    
-      
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+          
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@@ -1042,14 +1054,14 @@
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           Metrics and Monitoring
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@@ -1145,11 +1157,8 @@
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-    
-      
-      
-      
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+          
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@@ -1157,14 +1166,14 @@
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           <span class="md-nav__icon md-icon"></span>
           Security
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@@ -1248,6 +1257,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/linux_basics/intro/index.html b/linux_basics/intro/index.html
index 7185c73..d430f28 100644
--- a/linux_basics/intro/index.html
+++ b/linux_basics/intro/index.html
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       <label class="md-nav__link" for="nav-2-1">
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+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
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+      
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         Linux Basics
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       </label>
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           <span class="md-nav__icon md-icon"></span>
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@@ -397,14 +421,14 @@
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-      <label class="md-nav__link" for="nav-2-2">
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         Git
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       </label>
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           <span class="md-nav__icon md-icon"></span>
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-      <label class="md-nav__link" for="nav-2-3">
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         Linux Networking
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       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
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           <span class="md-nav__icon md-icon"></span>
           Linux Networking
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@@ -582,11 +606,8 @@
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-    
-      
-      
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+          
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@@ -594,14 +615,14 @@
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@@ -673,11 +694,8 @@
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-    
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@@ -685,14 +703,14 @@
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-      <label class="md-nav__link" for="nav-4-1">
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-      <label class="md-nav__link" for="nav-4-2">
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         NoSQL
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       </label>
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           <span class="md-nav__icon md-icon"></span>
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-      <label class="md-nav__link" for="nav-4-3">
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         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
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           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -1008,11 +1026,8 @@
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-    
-      
-      
-      
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+          
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@@ -1020,14 +1035,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
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       </label>
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+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
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           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1099,11 +1114,8 @@
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-    
-      
-      
-      
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+          
+            
   
   
   
@@ -1111,14 +1123,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
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           Metrics and Monitoring
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@@ -1214,11 +1226,8 @@
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-    
-      
-      
-      
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+          
+            
   
   
   
@@ -1226,14 +1235,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
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-      <label class="md-nav__link" for="nav-7">
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           <span class="md-nav__icon md-icon"></span>
           Security
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@@ -1317,6 +1326,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/linux_basics/linux_server_administration/index.html b/linux_basics/linux_server_administration/index.html
index 3cf31e0..cb77e19 100644
--- a/linux_basics/linux_server_administration/index.html
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-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
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-          Fundamentals Series
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       <label class="md-nav__link" for="nav-2-1">
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+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
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           <span class="md-nav__icon md-icon"></span>
           Linux Basics
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@@ -600,14 +624,14 @@
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-      <label class="md-nav__link" for="nav-2-2">
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       </label>
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@@ -676,14 +700,14 @@
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-      <label class="md-nav__link" for="nav-2-3">
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         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
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+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
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@@ -785,11 +809,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -797,14 +818,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -876,11 +897,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -888,14 +906,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
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@@ -910,14 +928,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
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@@ -1004,14 +1022,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
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@@ -1086,14 +1104,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
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@@ -1150,14 +1168,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -1211,11 +1229,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1223,14 +1238,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1302,11 +1317,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1314,14 +1326,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1417,11 +1429,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1429,14 +1438,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1520,6 +1529,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/linux_networking/conclusion/index.html b/linux_networking/conclusion/index.html
index 16d216d..e606eed 100644
--- a/linux_networking/conclusion/index.html
+++ b/linux_networking/conclusion/index.html
@@ -186,11 +186,35 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
+        Level 101
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
+        <label class="md-nav__title" for="nav-2">
+          <span class="md-nav__icon md-icon"></span>
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+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+    
+  
+  
+    
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
+      
+      
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+      
+      <label class="md-nav__link" for="nav-2-1">
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       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
-        <label class="md-nav__title" for="nav-2">
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
           <span class="md-nav__icon md-icon"></span>
           Fundamentals Series
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@@ -205,14 +229,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
       
-      <label class="md-nav__link" for="nav-2-1">
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -281,14 +305,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
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         <span class="md-nav__icon md-icon"></span>
       </label>
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-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
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@@ -359,14 +383,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" checked>
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
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         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -477,11 +501,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -489,14 +510,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
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         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
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           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -568,11 +589,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -580,14 +598,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
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@@ -602,14 +620,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
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@@ -696,14 +714,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -778,14 +796,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
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@@ -842,14 +860,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -903,11 +921,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -915,14 +930,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -994,11 +1009,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1006,14 +1018,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
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         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1109,11 +1121,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1121,14 +1130,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1212,6 +1221,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/linux_networking/dns/index.html b/linux_networking/dns/index.html
index 3d2300e..ada175d 100644
--- a/linux_networking/dns/index.html
+++ b/linux_networking/dns/index.html
@@ -186,11 +186,35 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
+        Level 101
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
+        <label class="md-nav__title" for="nav-2">
+          <span class="md-nav__icon md-icon"></span>
+          Level 101
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+    
+  
+  
+    
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" checked>
+      
+      <label class="md-nav__link" for="nav-2-1">
         Fundamentals Series
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
-        <label class="md-nav__title" for="nav-2">
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
           <span class="md-nav__icon md-icon"></span>
           Fundamentals Series
         </label>
@@ -205,14 +229,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
       
-      <label class="md-nav__link" for="nav-2-1">
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -281,14 +305,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -359,14 +383,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" checked>
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -506,11 +530,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -518,14 +539,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -597,11 +618,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -609,14 +627,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -631,14 +649,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -725,14 +743,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -807,14 +825,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -871,14 +889,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -932,11 +950,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -944,14 +959,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1023,11 +1038,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1035,14 +1047,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1138,11 +1150,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1150,14 +1159,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1241,6 +1250,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/linux_networking/http/index.html b/linux_networking/http/index.html
index 8f03806..8d754f7 100644
--- a/linux_networking/http/index.html
+++ b/linux_networking/http/index.html
@@ -186,11 +186,35 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
+        Level 101
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
+        <label class="md-nav__title" for="nav-2">
+          <span class="md-nav__icon md-icon"></span>
+          Level 101
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+    
+  
+  
+    
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" checked>
+      
+      <label class="md-nav__link" for="nav-2-1">
         Fundamentals Series
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
-        <label class="md-nav__title" for="nav-2">
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
           <span class="md-nav__icon md-icon"></span>
           Fundamentals Series
         </label>
@@ -205,14 +229,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
       
-      <label class="md-nav__link" for="nav-2-1">
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -281,14 +305,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -359,14 +383,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" checked>
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -477,11 +501,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -489,14 +510,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -568,11 +589,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -580,14 +598,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -602,14 +620,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -696,14 +714,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -778,14 +796,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -842,14 +860,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -903,11 +921,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -915,14 +930,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -994,11 +1009,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1006,14 +1018,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1109,11 +1121,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1121,14 +1130,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1212,6 +1221,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/linux_networking/intro/index.html b/linux_networking/intro/index.html
index b4af8c6..df6c952 100644
--- a/linux_networking/intro/index.html
+++ b/linux_networking/intro/index.html
@@ -186,11 +186,35 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
+        Level 101
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
+        <label class="md-nav__title" for="nav-2">
+          <span class="md-nav__icon md-icon"></span>
+          Level 101
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+    
+  
+  
+    
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" checked>
+      
+      <label class="md-nav__link" for="nav-2-1">
         Fundamentals Series
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
-        <label class="md-nav__title" for="nav-2">
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
           <span class="md-nav__icon md-icon"></span>
           Fundamentals Series
         </label>
@@ -205,14 +229,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
       
-      <label class="md-nav__link" for="nav-2-1">
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -281,14 +305,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -359,14 +383,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" checked>
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -534,11 +558,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -546,14 +567,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -625,11 +646,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -637,14 +655,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
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@@ -659,14 +677,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
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@@ -753,14 +771,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -835,14 +853,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -899,14 +917,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -960,11 +978,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -972,14 +987,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1051,11 +1066,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1063,14 +1075,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1166,11 +1178,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1178,14 +1187,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1269,6 +1278,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/linux_networking/ipr/index.html b/linux_networking/ipr/index.html
index 3d059c7..0de1b06 100644
--- a/linux_networking/ipr/index.html
+++ b/linux_networking/ipr/index.html
@@ -186,11 +186,35 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
+        Level 101
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
+        <label class="md-nav__title" for="nav-2">
+          <span class="md-nav__icon md-icon"></span>
+          Level 101
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+    
+  
+  
+    
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" checked>
+      
+      <label class="md-nav__link" for="nav-2-1">
         Fundamentals Series
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
-        <label class="md-nav__title" for="nav-2">
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
           <span class="md-nav__icon md-icon"></span>
           Fundamentals Series
         </label>
@@ -205,14 +229,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
       
-      <label class="md-nav__link" for="nav-2-1">
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -281,14 +305,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -359,14 +383,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" checked>
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -506,11 +530,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -518,14 +539,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
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       </label>
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@@ -597,11 +618,8 @@
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-      
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-      <label class="md-nav__link" for="nav-4-3">
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           Big Data
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@@ -932,11 +950,8 @@
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-    
-      
-      
-      
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+          
+            
   
   
   
@@ -944,14 +959,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
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           Systems Design
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@@ -1023,11 +1038,8 @@
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-    
-      
-      
-      
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+          
+            
   
   
   
@@ -1035,14 +1047,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
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@@ -1138,11 +1150,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1150,14 +1159,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
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           Security
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@@ -1241,6 +1250,12 @@
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+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/linux_networking/tcp/index.html b/linux_networking/tcp/index.html
index 7c9c730..b97a872 100644
--- a/linux_networking/tcp/index.html
+++ b/linux_networking/tcp/index.html
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           <span class="md-nav__icon md-icon"></span>
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@@ -205,14 +229,14 @@
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-      <label class="md-nav__link" for="nav-2-1">
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+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
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@@ -281,14 +305,14 @@
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-      <label class="md-nav__link" for="nav-2-2">
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@@ -506,11 +530,8 @@
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@@ -518,14 +539,14 @@
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@@ -597,11 +618,8 @@
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-    
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@@ -609,14 +627,14 @@
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-      <label class="md-nav__link" for="nav-4-1">
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+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
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-      <label class="md-nav__link" for="nav-4-1-7">
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@@ -807,14 +825,14 @@
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-      <label class="md-nav__link" for="nav-4-2">
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@@ -871,14 +889,14 @@
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-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
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           <span class="md-nav__icon md-icon"></span>
           Big Data
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@@ -932,11 +950,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -944,14 +959,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
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           Systems Design
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@@ -1023,11 +1038,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1035,14 +1047,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
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           Metrics and Monitoring
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@@ -1138,11 +1150,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1150,14 +1159,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
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-      <label class="md-nav__link" for="nav-7">
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@@ -1241,6 +1250,12 @@
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+          
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+  
+
     
       
       
diff --git a/linux_networking/udp/index.html b/linux_networking/udp/index.html
index 640dff2..7269983 100644
--- a/linux_networking/udp/index.html
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       <label class="md-nav__link" for="nav-2">
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+  
+  
+    
+  
+  
+    
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" checked>
+      
+      <label class="md-nav__link" for="nav-2-1">
         Fundamentals Series
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
-        <label class="md-nav__title" for="nav-2">
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
           <span class="md-nav__icon md-icon"></span>
           Fundamentals Series
         </label>
@@ -205,14 +229,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
       
-      <label class="md-nav__link" for="nav-2-1">
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -281,14 +305,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -359,14 +383,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" checked>
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -506,11 +530,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -518,14 +539,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -597,11 +618,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -609,14 +627,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -631,14 +649,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -725,14 +743,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -807,14 +825,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -871,14 +889,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -932,11 +950,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -944,14 +959,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1023,11 +1038,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1035,14 +1047,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1138,11 +1150,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1150,14 +1159,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1241,6 +1250,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/metrics_and_monitoring/alerts/index.html b/metrics_and_monitoring/alerts/index.html
index 32af318..f75a02c 100644
--- a/metrics_and_monitoring/alerts/index.html
+++ b/metrics_and_monitoring/alerts/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -567,14 +585,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -589,14 +607,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -683,14 +701,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -765,14 +783,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -829,14 +847,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -890,11 +908,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -902,14 +917,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -981,11 +996,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -995,14 +1007,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" checked>
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1107,11 +1119,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1119,14 +1128,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1210,6 +1219,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/metrics_and_monitoring/best_practices/index.html b/metrics_and_monitoring/best_practices/index.html
index 1c6692d..768e9a2 100644
--- a/metrics_and_monitoring/best_practices/index.html
+++ b/metrics_and_monitoring/best_practices/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -567,14 +585,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -589,14 +607,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -683,14 +701,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -765,14 +783,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -829,14 +847,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -890,11 +908,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -902,14 +917,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -981,11 +996,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -995,14 +1007,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" checked>
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1107,11 +1119,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1119,14 +1128,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1210,6 +1219,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/metrics_and_monitoring/command-line_tools/index.html b/metrics_and_monitoring/command-line_tools/index.html
index c8fa88b..57dd8be 100644
--- a/metrics_and_monitoring/command-line_tools/index.html
+++ b/metrics_and_monitoring/command-line_tools/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -567,14 +585,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -589,14 +607,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -683,14 +701,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
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@@ -765,14 +783,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -829,14 +847,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -890,11 +908,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -902,14 +917,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -981,11 +996,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -995,14 +1007,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" checked>
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1107,11 +1119,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1119,14 +1128,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1210,6 +1219,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/metrics_and_monitoring/conclusion/index.html b/metrics_and_monitoring/conclusion/index.html
index a59df86..db652e7 100644
--- a/metrics_and_monitoring/conclusion/index.html
+++ b/metrics_and_monitoring/conclusion/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
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@@ -206,11 +208,33 @@
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       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
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@@ -355,14 +379,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -567,14 +585,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
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@@ -589,14 +607,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -683,14 +701,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -765,14 +783,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
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@@ -829,14 +847,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -890,11 +908,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -902,14 +917,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -981,11 +996,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -995,14 +1007,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" checked>
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1136,11 +1148,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1148,14 +1157,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1239,6 +1248,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/metrics_and_monitoring/introduction/index.html b/metrics_and_monitoring/introduction/index.html
index f1c05e0..3b217bc 100644
--- a/metrics_and_monitoring/introduction/index.html
+++ b/metrics_and_monitoring/introduction/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
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         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -567,14 +585,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -589,14 +607,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -683,14 +701,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -765,14 +783,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -829,14 +847,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -890,11 +908,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -902,14 +917,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -981,11 +996,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -995,14 +1007,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" checked>
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1107,11 +1119,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1119,14 +1128,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1210,6 +1219,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/metrics_and_monitoring/observability/index.html b/metrics_and_monitoring/observability/index.html
index 050a67e..d2f69fc 100644
--- a/metrics_and_monitoring/observability/index.html
+++ b/metrics_and_monitoring/observability/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -567,14 +585,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
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           Data
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@@ -589,14 +607,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
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@@ -683,14 +701,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
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@@ -765,14 +783,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
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@@ -829,14 +847,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -890,11 +908,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -902,14 +917,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -981,11 +996,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -995,14 +1007,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" checked>
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1107,11 +1119,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1119,14 +1128,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1210,6 +1219,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/metrics_and_monitoring/third-party_monitoring/index.html b/metrics_and_monitoring/third-party_monitoring/index.html
index e84d15d..e3e3ebe 100644
--- a/metrics_and_monitoring/third-party_monitoring/index.html
+++ b/metrics_and_monitoring/third-party_monitoring/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -567,14 +585,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -589,14 +607,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -683,14 +701,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -765,14 +783,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -829,14 +847,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -890,11 +908,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -902,14 +917,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -981,11 +996,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -995,14 +1007,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" checked>
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1107,11 +1119,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1119,14 +1128,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1210,6 +1219,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/python_web/intro/index.html b/python_web/intro/index.html
index 257c6fa..05e0c85 100644
--- a/python_web/intro/index.html
+++ b/python_web/intro/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -478,14 +499,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" checked>
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -650,11 +671,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -662,14 +680,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
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@@ -684,14 +702,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
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@@ -778,14 +796,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -860,14 +878,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -924,14 +942,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -985,11 +1003,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -997,14 +1012,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1076,11 +1091,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1088,14 +1100,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1191,11 +1203,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1203,14 +1212,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1294,6 +1303,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/python_web/python-concepts/index.html b/python_web/python-concepts/index.html
index b014f75..a74e940 100644
--- a/python_web/python-concepts/index.html
+++ b/python_web/python-concepts/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -478,14 +499,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" checked>
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -629,11 +650,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -641,14 +659,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
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@@ -663,14 +681,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -757,14 +775,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -839,14 +857,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -903,14 +921,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -964,11 +982,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -976,14 +991,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1055,11 +1070,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1067,14 +1079,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1170,11 +1182,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1182,14 +1191,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1273,6 +1282,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/python_web/python-web-flask/index.html b/python_web/python-web-flask/index.html
index a811a9d..781c9ee 100644
--- a/python_web/python-web-flask/index.html
+++ b/python_web/python-web-flask/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
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         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -478,14 +499,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" checked>
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -602,11 +623,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -614,14 +632,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -636,14 +654,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -730,14 +748,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -812,14 +830,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -876,14 +894,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -937,11 +955,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -949,14 +964,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1028,11 +1043,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1040,14 +1052,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1143,11 +1155,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1155,14 +1164,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1246,6 +1255,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/python_web/sre-conclusion/index.html b/python_web/sre-conclusion/index.html
index 443a4c7..e229f4a 100644
--- a/python_web/sre-conclusion/index.html
+++ b/python_web/sre-conclusion/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -478,14 +499,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" checked>
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -623,11 +644,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -635,14 +653,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -657,14 +675,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -751,14 +769,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -833,14 +851,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -897,14 +915,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -958,11 +976,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -970,14 +985,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1049,11 +1064,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1061,14 +1073,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1164,11 +1176,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1176,14 +1185,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1267,6 +1276,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/python_web/url-shorten-app/index.html b/python_web/url-shorten-app/index.html
index f8ce09d..c4e5407 100644
--- a/python_web/url-shorten-app/index.html
+++ b/python_web/url-shorten-app/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -478,14 +499,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" checked>
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -636,11 +657,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -648,14 +666,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -670,14 +688,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -764,14 +782,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -846,14 +864,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -910,14 +928,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -971,11 +989,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -983,14 +998,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1062,11 +1077,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1074,14 +1086,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1177,11 +1189,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1189,14 +1198,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1280,6 +1289,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/security/conclusion/index.html b/security/conclusion/index.html
index f00940b..57276ed 100644
--- a/security/conclusion/index.html
+++ b/security/conclusion/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -567,14 +585,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -589,14 +607,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -683,14 +701,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -765,14 +783,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -829,14 +847,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -890,11 +908,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -902,14 +917,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -981,11 +996,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -993,14 +1005,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1096,11 +1108,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -1110,14 +1119,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" checked>
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1246,6 +1255,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/security/fundamentals/index.html b/security/fundamentals/index.html
index e662858..b259f7b 100644
--- a/security/fundamentals/index.html
+++ b/security/fundamentals/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -567,14 +585,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -589,14 +607,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -683,14 +701,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -765,14 +783,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -829,14 +847,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -890,11 +908,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -902,14 +917,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -981,11 +996,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -993,14 +1005,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1096,11 +1108,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -1110,14 +1119,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" checked>
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1334,6 +1343,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/security/intro/index.html b/security/intro/index.html
index 825fa3d..bcf2edb 100644
--- a/security/intro/index.html
+++ b/security/intro/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
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+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -567,14 +585,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -589,14 +607,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -683,14 +701,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -765,14 +783,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -829,14 +847,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -890,11 +908,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -902,14 +917,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -981,11 +996,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -993,14 +1005,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1096,11 +1108,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -1110,14 +1119,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" checked>
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1260,6 +1269,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/security/network_security/index.html b/security/network_security/index.html
index 5bc42c7..27439a9 100644
--- a/security/network_security/index.html
+++ b/security/network_security/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
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+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -567,14 +585,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
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@@ -589,14 +607,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -683,14 +701,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -765,14 +783,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
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@@ -829,14 +847,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -890,11 +908,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -902,14 +917,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
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           <span class="md-nav__icon md-icon"></span>
           Systems Design
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@@ -981,11 +996,8 @@
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-    
-      
-      
-      
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+          
+            
   
   
   
@@ -993,14 +1005,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
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         Metrics and Monitoring
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       </label>
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           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1096,11 +1108,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -1110,14 +1119,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" checked>
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
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           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1445,6 +1454,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/security/threats_attacks_defences/index.html b/security/threats_attacks_defences/index.html
index e4cd51e..8296e35 100644
--- a/security/threats_attacks_defences/index.html
+++ b/security/threats_attacks_defences/index.html
@@ -176,21 +176,23 @@
 
   
   
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+  
   
     
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       <label class="md-nav__link" for="nav-2">
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-          Fundamentals Series
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@@ -206,11 +208,33 @@
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       <label class="md-nav__link" for="nav-2-1">
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+          Fundamentals Series
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+          
+          
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+  
+  
+    
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+      
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+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
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       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
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@@ -279,14 +303,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
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         Git
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       </label>
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+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
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@@ -355,14 +379,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
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         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
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+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
           Linux Networking
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@@ -464,11 +488,8 @@
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-    
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+          
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@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
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-      <label class="md-nav__link" for="nav-3">
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         Python and Web
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       </label>
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+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
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           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
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-    
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-      
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+          
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@@ -567,14 +585,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
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+      <nav class="md-nav" aria-label="Data" data-md-level="2">
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@@ -589,14 +607,14 @@
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-      <label class="md-nav__link" for="nav-4-1">
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-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
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-      <label class="md-nav__link" for="nav-4-1-7">
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-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
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@@ -765,14 +783,14 @@
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-      <label class="md-nav__link" for="nav-4-2">
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         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
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           <span class="md-nav__icon md-icon"></span>
           NoSQL
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@@ -829,14 +847,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -890,11 +908,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -902,14 +917,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
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+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
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           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -981,11 +996,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -993,14 +1005,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
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       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
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           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1096,11 +1108,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -1110,14 +1119,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" checked>
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
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-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
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           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1493,6 +1502,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/security/writing_secure_code/index.html b/security/writing_secure_code/index.html
index 9422dd9..7cb92ad 100644
--- a/security/writing_secure_code/index.html
+++ b/security/writing_secure_code/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
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         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
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           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
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@@ -206,11 +208,33 @@
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       <label class="md-nav__link" for="nav-2-1">
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+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
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       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
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           <span class="md-nav__icon md-icon"></span>
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@@ -279,14 +303,14 @@
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-      <label class="md-nav__link" for="nav-2-2">
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       </label>
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           <span class="md-nav__icon md-icon"></span>
           Git
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@@ -355,14 +379,14 @@
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-      <label class="md-nav__link" for="nav-2-3">
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           Linux Networking
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@@ -464,11 +488,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
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           <span class="md-nav__icon md-icon"></span>
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@@ -555,11 +576,8 @@
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-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -567,14 +585,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
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-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -589,14 +607,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -683,14 +701,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -765,14 +783,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -829,14 +847,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -890,11 +908,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -902,14 +917,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -981,11 +996,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -993,14 +1005,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1096,11 +1108,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -1110,14 +1119,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" checked>
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1315,6 +1324,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/sitemap.xml b/sitemap.xml
index c7e0a90..eb85679 100644
--- a/sitemap.xml
+++ b/sitemap.xml
@@ -1,235 +1,235 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url><url>
      <loc>None</loc>
-     <lastmod>2021-08-03</lastmod>
+     <lastmod>2021-08-04</lastmod>
      <changefreq>daily</changefreq>
     </url>
 </urlset>
\ No newline at end of file
diff --git a/sitemap.xml.gz b/sitemap.xml.gz
index 9f192a571737fc252658b941279336f795a6cc11..93bc8cfe8dd3ba453fdf4d041274f207524f4d46 100644
GIT binary patch
delta 204
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z&-ssm@z-<Hbi7%+d)LNZzP&AF`e#GUh^0!E^VyB;;!aQVx>ji~YY{(9b?Lp?f&No=
z?R*+i{<{5#Skc6HGr4wabse7Ay!z_NNaf0kT4&$7lHOCU^Hdjk9LbZ-zZtgD+9o%;
yc<xzW(_Qj$lm4sB?|ahN$jU9I6R{!TU=upy?{?8zJ)^k2jG4yMd!I@$FaQ9b;9GwH

delta 203
zcmaFBc%PA7zMF$XT$ghqyIg(Vg(;hgUwZLha9|b6n7DG$_UTeSHqAfpZu$FJ-9PMn
zVTXL$vU@itrLIiaxN&QC)$M6-itN-_SBI#)|Lkz=c=pYplUDDSGe1AQX~~sp<5!(Q
z=G*7I%KIyD-%0P1ZE#|^YoSF^!B#8FY!&|X`72KLuM6CHVzY}#=Z&?Gb#H5xF1OCj
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diff --git a/sre_community/index.html b/sre_community/index.html
index 222a68a..504eec5 100644
--- a/sre_community/index.html
+++ b/sre_community/index.html
@@ -179,13 +179,13 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -201,11 +201,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -274,14 +296,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -350,14 +372,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -459,11 +481,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -471,14 +490,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -550,11 +569,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -562,14 +578,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -584,14 +600,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -678,14 +694,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -760,14 +776,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -824,14 +840,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -885,11 +901,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -897,14 +910,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" >
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -976,11 +989,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -988,14 +998,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1091,11 +1101,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1103,14 +1110,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1194,6 +1201,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/systems_design/availability/index.html b/systems_design/availability/index.html
index 8dbfd6c..133a735 100644
--- a/systems_design/availability/index.html
+++ b/systems_design/availability/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -567,14 +585,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -589,14 +607,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -683,14 +701,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -765,14 +783,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -829,14 +847,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -890,11 +908,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -904,14 +919,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" checked>
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1102,11 +1117,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1114,14 +1126,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1217,11 +1229,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1229,14 +1238,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1320,6 +1329,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/systems_design/conclusion/index.html b/systems_design/conclusion/index.html
index 9b87d07..be1db78 100644
--- a/systems_design/conclusion/index.html
+++ b/systems_design/conclusion/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -567,14 +585,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -589,14 +607,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -683,14 +701,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -765,14 +783,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -829,14 +847,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -890,11 +908,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -904,14 +919,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" checked>
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -992,11 +1007,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1004,14 +1016,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1107,11 +1119,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1119,14 +1128,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1210,6 +1219,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/systems_design/fault-tolerance/index.html b/systems_design/fault-tolerance/index.html
index 2c03a6c..3c8049d 100644
--- a/systems_design/fault-tolerance/index.html
+++ b/systems_design/fault-tolerance/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -567,14 +585,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -589,14 +607,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -683,14 +701,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
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@@ -765,14 +783,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -829,14 +847,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -890,11 +908,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -904,14 +919,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" checked>
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1075,11 +1090,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1087,14 +1099,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1190,11 +1202,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1202,14 +1211,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1293,6 +1302,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/systems_design/intro/index.html b/systems_design/intro/index.html
index affe9b8..9a3313d 100644
--- a/systems_design/intro/index.html
+++ b/systems_design/intro/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -567,14 +585,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -589,14 +607,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -683,14 +701,14 @@
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-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -765,14 +783,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -829,14 +847,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -890,11 +908,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -904,14 +919,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" checked>
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1056,11 +1071,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1068,14 +1080,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1171,11 +1183,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1183,14 +1192,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1274,6 +1283,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+
     
       
       
diff --git a/systems_design/scalability/index.html b/systems_design/scalability/index.html
index e60a277..dd633a2 100644
--- a/systems_design/scalability/index.html
+++ b/systems_design/scalability/index.html
@@ -176,21 +176,23 @@
 
   
   
+    
+  
   
     
-    <li class="md-nav__item md-nav__item--nested">
+    <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2" type="checkbox" id="nav-2" checked>
       
       <label class="md-nav__link" for="nav-2">
-        Fundamentals Series
+        Level 101
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="1">
+      <nav class="md-nav" aria-label="Level 101" data-md-level="1">
         <label class="md-nav__title" for="nav-2">
           <span class="md-nav__icon md-icon"></span>
-          Fundamentals Series
+          Level 101
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           
@@ -206,11 +208,33 @@
         <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1" type="checkbox" id="nav-2-1" >
       
       <label class="md-nav__link" for="nav-2-1">
+        Fundamentals Series
+        <span class="md-nav__icon md-icon"></span>
+      </label>
+      <nav class="md-nav" aria-label="Fundamentals Series" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-1">
+          <span class="md-nav__icon md-icon"></span>
+          Fundamentals Series
+        </label>
+        <ul class="md-nav__list" data-md-scrollfix>
+          
+          
+            
+  
+  
+  
+    
+    <li class="md-nav__item md-nav__item--nested">
+      
+      
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-1" type="checkbox" id="nav-2-1-1" >
+      
+      <label class="md-nav__link" for="nav-2-1-1">
         Linux Basics
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Basics" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-1">
+      <nav class="md-nav" aria-label="Linux Basics" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-1">
           <span class="md-nav__icon md-icon"></span>
           Linux Basics
         </label>
@@ -279,14 +303,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-2" type="checkbox" id="nav-2-1-2" >
       
-      <label class="md-nav__link" for="nav-2-2">
+      <label class="md-nav__link" for="nav-2-1-2">
         Git
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Git" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-2">
+      <nav class="md-nav" aria-label="Git" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-2">
           <span class="md-nav__icon md-icon"></span>
           Git
         </label>
@@ -355,14 +379,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-1-3" type="checkbox" id="nav-2-1-3" >
       
-      <label class="md-nav__link" for="nav-2-3">
+      <label class="md-nav__link" for="nav-2-1-3">
         Linux Networking
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Linux Networking" data-md-level="2">
-        <label class="md-nav__title" for="nav-2-3">
+      <nav class="md-nav" aria-label="Linux Networking" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-1-3">
           <span class="md-nav__icon md-icon"></span>
           Linux Networking
         </label>
@@ -464,11 +488,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -476,14 +497,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-2" type="checkbox" id="nav-2-2" >
       
-      <label class="md-nav__link" for="nav-3">
+      <label class="md-nav__link" for="nav-2-2">
         Python and Web
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Python and Web" data-md-level="1">
-        <label class="md-nav__title" for="nav-3">
+      <nav class="md-nav" aria-label="Python and Web" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-2">
           <span class="md-nav__icon md-icon"></span>
           Python and Web
         </label>
@@ -555,11 +576,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -567,14 +585,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3" type="checkbox" id="nav-2-3" >
       
-      <label class="md-nav__link" for="nav-4">
+      <label class="md-nav__link" for="nav-2-3">
         Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Data" data-md-level="1">
-        <label class="md-nav__title" for="nav-4">
+      <nav class="md-nav" aria-label="Data" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-3">
           <span class="md-nav__icon md-icon"></span>
           Data
         </label>
@@ -589,14 +607,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1" type="checkbox" id="nav-4-1" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1" type="checkbox" id="nav-2-3-1" >
       
-      <label class="md-nav__link" for="nav-4-1">
+      <label class="md-nav__link" for="nav-2-3-1">
         Relational Databases
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Relational Databases" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-1">
+      <nav class="md-nav" aria-label="Relational Databases" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-1">
           <span class="md-nav__icon md-icon"></span>
           Relational Databases
         </label>
@@ -683,14 +701,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-1-7" type="checkbox" id="nav-4-1-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-1-7" type="checkbox" id="nav-2-3-1-7" >
       
-      <label class="md-nav__link" for="nav-4-1-7">
+      <label class="md-nav__link" for="nav-2-3-1-7">
         Operational Concepts
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="3">
-        <label class="md-nav__title" for="nav-4-1-7">
+      <nav class="md-nav" aria-label="Operational Concepts" data-md-level="4">
+        <label class="md-nav__title" for="nav-2-3-1-7">
           <span class="md-nav__icon md-icon"></span>
           Operational Concepts
         </label>
@@ -765,14 +783,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-2" type="checkbox" id="nav-4-2" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-2" type="checkbox" id="nav-2-3-2" >
       
-      <label class="md-nav__link" for="nav-4-2">
+      <label class="md-nav__link" for="nav-2-3-2">
         NoSQL
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="NoSQL" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-2">
+      <nav class="md-nav" aria-label="NoSQL" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-2">
           <span class="md-nav__icon md-icon"></span>
           NoSQL
         </label>
@@ -829,14 +847,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-4-3" type="checkbox" id="nav-4-3" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-3-3" type="checkbox" id="nav-2-3-3" >
       
-      <label class="md-nav__link" for="nav-4-3">
+      <label class="md-nav__link" for="nav-2-3-3">
         Big Data
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Big Data" data-md-level="2">
-        <label class="md-nav__title" for="nav-4-3">
+      <nav class="md-nav" aria-label="Big Data" data-md-level="3">
+        <label class="md-nav__title" for="nav-2-3-3">
           <span class="md-nav__icon md-icon"></span>
           Big Data
         </label>
@@ -890,11 +908,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
     
@@ -904,14 +919,14 @@
     <li class="md-nav__item md-nav__item--active md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" checked>
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-4" type="checkbox" id="nav-2-4" checked>
       
-      <label class="md-nav__link" for="nav-5">
+      <label class="md-nav__link" for="nav-2-4">
         Systems Design
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Systems Design" data-md-level="1">
-        <label class="md-nav__title" for="nav-5">
+      <nav class="md-nav" aria-label="Systems Design" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-4">
           <span class="md-nav__icon md-icon"></span>
           Systems Design
         </label>
@@ -1197,11 +1212,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1209,14 +1221,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-5" type="checkbox" id="nav-2-5" >
       
-      <label class="md-nav__link" for="nav-6">
+      <label class="md-nav__link" for="nav-2-5">
         Metrics and Monitoring
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="1">
-        <label class="md-nav__title" for="nav-6">
+      <nav class="md-nav" aria-label="Metrics and Monitoring" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-5">
           <span class="md-nav__icon md-icon"></span>
           Metrics and Monitoring
         </label>
@@ -1312,11 +1324,8 @@
     </li>
   
 
-    
-      
-      
-      
-
+          
+            
   
   
   
@@ -1324,14 +1333,14 @@
     <li class="md-nav__item md-nav__item--nested">
       
       
-        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7" >
+        <input class="md-nav__toggle md-toggle" data-md-toggle="nav-2-6" type="checkbox" id="nav-2-6" >
       
-      <label class="md-nav__link" for="nav-7">
+      <label class="md-nav__link" for="nav-2-6">
         Security
         <span class="md-nav__icon md-icon"></span>
       </label>
-      <nav class="md-nav" aria-label="Security" data-md-level="1">
-        <label class="md-nav__title" for="nav-7">
+      <nav class="md-nav" aria-label="Security" data-md-level="2">
+        <label class="md-nav__title" for="nav-2-6">
           <span class="md-nav__icon md-icon"></span>
           Security
         </label>
@@ -1415,6 +1424,12 @@
     </li>
   
 
+          
+        </ul>
+      </nav>
+    </li>
+  
+