@scope

@scope (scope root) to (scope limit) {
  …
}

<div>
  <style>
    @scope {
      …
    }
  </style>
</div>

@scope (.Card) {
  > header,
  > footer {
    background: hsl(none none none / 20%);
  }
}

@scope (.light) {
  :scope { background: white }
  a      { color: blue }
}

@scope (.dark) {
  :scope { background: darkslategray }
  a      { color: lightblue }
}