Add reference for border type.

docs/css_types/border.md

@@ -0,0 +1,51 @@
+# <border>
+
+The `<border>` CSS type represents a border style.
+
+## Syntax
+
+--8<-- "docs/snippets/type_syntax/border.md"
+
+## Examples
+
+### CSS
+
+```sass
+* {
+    rule: "ascii"   /* A border with plus, hyphen, and vertical bar characters. */
+    rule: "blank"   /* A blank border (reserves space for a border). */
+    rule: "dashed"  /* Dashed line border. */
+    rule: "double"  /* Double lined border. */
+    rule: "heavy"   /* Heavy border. */
+    rule: "hidden"  /* Alias for "none". */
+    rule: "hkey"    /* Horizontal key-line border. */
+    rule: "inner"   /* Thick solid border. */
+    rule: "none"    /* Disabled border. */
+    rule: "outer"   /* Solid border with additional space around content. */
+    rule: "round"   /* Rounded corners. */
+    rule: "solid"   /* Solid border. */
+    rule: "tall"    /* Solid border with additional space top and bottom. */
+    rule: "vkey"    /* Vertical key-line border. */
+    rule: "wide"    /* Solid border with additional space left and right. */
+}
+```
+
+### Python
+
+```py
+border: "ascii"   # A border with plus, hyphen, and vertical bar characters.
+border: "blank"   # A blank border (reserves space for a border).
+border: "dashed"  # Dashed line border.
+border: "double"  # Double lined border.
+border: "heavy"   # Heavy border.
+border: "hidden"  # Alias for "none".
+border: "hkey"    # Horizontal key-line border.
+border: "inner"   # Thick solid border.
+border: "none"    # Disabled border.
+border: "outer"   # Solid border with additional space around content.
+border: "round"   # Rounded corners.
+border: "solid"   # Solid border.
+border: "tall"    # Solid border with extras space top and bottom.
+border: "vkey"    # Vertical key-line border.
+border: "wide"    # Solid border with additional space left and right.
+```

docs/snippets/type_syntax/border.md

@@ -0,0 +1,19 @@
+The [`<border>`](/css_types/border.md) type can take any of the following values:
+
+| Border type | Description                                              |
+|-------------|----------------------------------------------------------|
+| `"ascii"`   | A border with plus, hyphen, and vertical bar characters. |
+| `"blank"`   | A blank border (reserves space for a border).            |
+| `"dashed"`  | Dashed line border.                                      |
+| `"double"`  | Double lined border.                                     |
+| `"heavy"`   | Heavy border.                                            |
+| `"hidden"`  | Alias for "none".                                        |
+| `"hkey"`    | Horizontal key-line border.                              |
+| `"inner"`   | Thick solid border.                                      |
+| `"none"`    | Disabled border.                                         |
+| `"outer"`   | Solid border with additional space around content.       |
+| `"round"`   | Rounded corners.                                         |
+| `"solid"`   | Solid border.                                            |
+| `"tall"`    | Solid border with additional space top and bottom.       |
+| `"vkey"`    | Vertical key-line border.                                |
+| `"wide"`    | Solid border with additional space left and right.       |

mkdocs.yml

@@ -30,6 +30,7 @@ nav:
     - "reference/index.md"
     - CSS Types:
       - "css_types/index.md"
+      - "css_types/border.md"
       - "css_types/color.md"
       - "css_types/horizontal.md"
       - "css_types/integer.md"