Dark theme support based on preference (#158)

Author: ok-nick

mkdocs.yml

@@ -8,8 +8,9 @@ theme:
   palette:
     primary: 'Light Blue'
     accent: 'Light Blue'
+    scheme: preference
 
-pages:
+nav:
   - Home: index.md
   - Getting Started:
     - Installation: getting-started/installation.md
@@ -24,4 +25,4 @@ markdown_extensions:
       guess_lang: false
   - toc:
       permalink: true
-  - pymdownx.superfences
+  - pymdownx.superfences