Add overflow CSS type.

docs/css_types/overflow.md

@@ -0,0 +1,27 @@
+# <overflow>
+
+The `<overflow>` CSS type represents overflow modes.
+
+## Syntax
+
+--8<-- "docs/snippets/type_syntax/overflow.md"
+
+## Examples
+
+### CSS
+
+```sass
+* {
+    rule: auto;    /* Determine overflow mode automatically. */
+    rule: hidden;  /* Don't overflow. */
+    rule: scroll;  /* Allow overflowing. */
+}
+```
+
+### Python
+
+```py
+overflow = "auto"    # Determine overflow mode automatically.
+overflow = "hidden"  # Don't overflow.
+overflow = "scroll"  # Allow overflowing.
+```

docs/snippets/type_syntax/overflow.md

@@ -0,0 +1,7 @@
+The [`<overflow>`](/css_types/overflow) type can take any of the following values:
+
+| Value    | Description                            |
+|----------|----------------------------------------|
+| `auto`   | Determine overflow mode automatically. |
+| `hidden` | Don't overflow.                        |
+| `scroll` | Allow overflowing.                     |

mkdocs.yml

@@ -36,6 +36,7 @@ nav:
       - "css_types/integer.md"
       - "css_types/name.md"
       - "css_types/number.md"
+      - "css_types/overflow.md"
       - "css_types/percentage.md"
       - "css_types/scalar.md"
       - "css_types/text_style.md"