Thanks to visit codestin.com
Credit goes to modelcontextprotocol.github.io

Function applyDocumentTheme

applyDocumentTheme(theme: McpUiTheme): void
Apply a theme to the document root element.

Sets the data-theme attribute and CSS color-scheme property on document.documentElement. This enables CSS selectors like [data-theme="dark"] and ensures native elements (scrollbars, form controls) respect the theme.
Parameters
- theme: McpUiTheme
  The theme to apply ("light" or "dark")
Returns void
Example: Apply theme from host context
```
import { applyDocumentTheme } from '@modelcontextprotocol/ext-apps';

app.onhostcontextchanged = (params) => {
  if (params.theme) {
    applyDocumentTheme(params.theme);
  }
};
```
Example: Use with CSS selectors
```
[data-theme="dark"] {
  --bg-color: #1a1a1a;
}
[data-theme="light"] {
  --bg-color: #ffffff;
}
```
See
- getDocumentTheme to read the current theme
- McpUiTheme for the theme type
- Defined in src/styles.ts:70