CSS Tree-Counting Functions

The `sibling-index()` and `sibling-count()` functions, which expose an element's position and sibling total to CSS calculations.

Content tagged tree-counting-functions

• Tutorial:CSS-Only Staggered Animations with sibling-index() and sibling-count()

  Stagger animations from each element's own position, without JavaScript.

  sibling-index() and sibling-count() give an element its own 1-based position and its sibling total directly inside calc() — replacing the JavaScript loop that sets a --i custom property, with fixed-step and fixed-total staggers, index-driven colours and rotations, fallbacks, and reduced-motion handling.