1. :has() CSS relational pseudo-class

    Select elements containing specific content. For example, `a:has(img)` selects all `<a>` elements that contain an `<img>` child.

  2. CSS Nesting

    CSS nesting provides the ability to nest one style rule inside another, with the selector of the child rule relative to the selector of the parent rule. Similar behavior previously required a CSS pre-processor.

  3. css selector: `:first-child`: matches elements with no parent

  4. css selector: `:last-child`: matches elements with no parent

  5. css selector: `:nth-child()`: matches elements with no parent

  6. css selector: `:nth-last-child()`: matches elements with no parent

  7. css selector: `:only-child`: matches elements with no parent