1. Scoped Styles: the @scope rule

    Allows CSS rules to be scoped to part of the document, with upper and lower limits described by selectors.

  2. Scoped attribute

    Deprecated method of allowing scoped CSS styles using a "scoped" attribute. Now [removed from the specification](https://github.com/whatwg/html/issues/552) and replaced by the [@scope CSS rule](/css-cascade-scope).

  3. css at-rule: `@scope`