Add dark mode for theme

See https://squidfunk.github.io/mkdocs-material/setup/changing-the-colors/?h=dark#automatic-light-dark-mode

mkdocs.yml

@@ -14,6 +14,24 @@ markdown_extensions:
     - pymdownx.highlight:
         use_pygments: true
 theme:
+    palette:
+        # Palette toggle for automatic mode
+        - media: "(prefers-color-scheme)"
+          toggle:
+              icon: material/brightness-auto
+              name: Switch to light mode
+        # Palette toggle for light mode
+        - media: "(prefers-color-scheme: light)"
+          scheme: default 
+          toggle:
+              icon: material/brightness-7
+              name: Switch to dark mode
+        # Palette toggle for dark mode
+        - media: "(prefers-color-scheme: dark)"
+          scheme: slate
+          toggle:
+              icon: material/brightness-4
+              name: Switch to system preference
     name: material
     features:
         - tabs