Sync mkdocs and reference index with changes.

docs/reference/index.md

@@ -4,6 +4,15 @@ Welcome to the Textual Reference.
 
 <div class="grid cards" markdown>
 
+-   :octicons-book-16:{ .lg .middle } __CSS Types__
+
+    ---
+
+    CSS Types are the data types that CSS [styles](../styles/index.md) accept in their rules.
+
+    :octicons-arrow-right-24: [CSS Types Reference](../css_types/index.md)
+
+
 -   :octicons-book-16:{ .lg .middle } __Events__
 
     ---

mkdocs.yml

@@ -28,6 +28,14 @@ nav:
   - "roadmap.md"
   - Reference:
     - "reference/index.md"
+    - CSS Types:
+      - "css_types/index.md"
+      - "css_types/color.md"
+      - "css_types/fractional.md"
+      - "css_types/integer.md"
+      - "css_types/percentage.md"
+      - "css_types/scalar.md"
+      - "css_types/text_style.md"
     - Events:
       - "events/index.md"
       - "events/blur.md"
@@ -54,14 +62,6 @@ nav:
       - "events/screen_suspend.md"
       - "events/show.md"
     - Styles:
-      - CSS units:
-        - "styles/css_units/index.md"
-        - "styles/css_units/color.md"
-        - "styles/css_units/fractional.md"
-        - "styles/css_units/integer.md"
-        - "styles/css_units/percentage.md"
-        - "styles/css_units/scalar.md"
-        - "styles/css_units/text_style.md"
       - "styles/index.md"
       - "styles/align.md"
       - "styles/background.md"