docs(css): add border-inline term entry

content/css/concepts/background/terms/border-inline/border-inline.md

@@ -0,0 +1,58 @@
+---
+Title: 'border-inline'
+Description: 'Sets the width, style, and color of an element’s inline-start and inline-end borders.'
+Subjects:
+  - 'Web Design'
+  - 'Web Development'
+Tags:
+  - 'Borders'
+  - 'Box Model'
+  - 'Colors'
+CatalogContent:
+  - 'learn-css'
+  - 'paths/front-end-engineer-career-path'
+---
+
+The **`border-inline`** property is a shorthand property that sets the width, style, and color of an element’s inline-start and inline-end borders. The physical sides affected depend on the writing mode and text direction.
+
+## Syntax
+
+```pseudo
+border-inline: <value>;
+```
+
+**Parameters:**
+
+- `<value>`: May include one or more of the following, in any order:
+  - `<line-width>`: Sets the border thickness (e.g., `1px`, `thin`, `medium`, `thick`).
+  - `<line-style>`: Sets the border style (e.g., `solid`, `dashed`, `dotted`, `double`, `none`).
+  - `<color>`: Sets the border color (e.g., `red`, `#333`, `rgb(0 0 0)`).
+  - **Global values:** `inherit`, `initial`, `revert`, `revert-layer`, `unset`.
+
+If a single value is provided, it applies to both inline-start and inline-end borders.
+
+**Return value:**
+
+None. Sets the computed values of `border-inline-start` and `border-inline-end`.
+
+## Example 1
+
+The following example sets the inline borders of the `p` element to be blue, 2 pixels thick, and solid:
+
+```css
+p {
+  border-inline: 2px solid blue;
+}
+```
+
+## Example 2
+
+The following example set the inline borders of the `div` element to be red, 5 pixels thick, and dashed:
+
+```css
+div {
+  border-inline: dashed 5px red;
+}
+```
+
+In a left-to-right writing mode, this applies borders to the left and right sides of the element. In a right-to-left writing mode, the inline start and end sides adjust automatically.