Complete reference for column-span.

docs/styles/grid/column_span.md

@@ -1 +1,42 @@
 # Column-span
+
+The `column-span` style specifies how many rows a widget will span in a grid layout.
+
+## Syntax
+
+```sass
+column-span: <INTEGER>
+```
+
+## Example
+
+The example below shows a 4 by 4 grid where many placeholders span over several columns.
+
+=== "Output"
+
+    ```{.textual path="docs/examples/styles/column_span.py"}
+    ```
+
+=== "column_span.py"
+
+    ```py
+    --8<-- "docs/examples/styles/column_span.py"
+    ```
+
+=== "column_span.css"
+
+    ```css
+    --8<-- "docs/examples/styles/column_span.css"
+    ```
+
+## CSS
+
+```sass
+column-span: 3
+```
+
+## Python
+
+```py
+widget.styles.column_span = 3
+```