message: Cosmetic edit of extend-stylesheet
diff: # Extend Stylable stylesheet
  -Use the `-st-extends` directive rule to extend a CSS class with another stylesheet, in order to be able to describe styling of [pseudo classes](./pseudo-classes.md) and [pseudo elements](./pseudo-elements.md) of the extended stylesheet.
  +Use the `-st-extends` directive rule to extend a CSS class with another stylesheet. This enables you to style [pseudo classes](./pseudo-classes.md) and [pseudo elements](./pseudo-elements.md) of the extended stylesheet.
  -> *Note*: `-st-extends` may only be applied to [class selector](./class-selectors.md) and [root selector](./root.md).
  +> **Note**: `-st-extends` can be applied only to [class selectors](./class-selectors.md) and a [root selector](./root.md).
  +
  +In this example, the stylesheet is extending the `toggle-button.css` stylesheet. The `check-btn` class has a `label`, which is a custom pseudo-element, and can be `toggled`, a custom pseudo-class.
  ### CSS API:
  ```css
  