Reference

Affix

A nail: the wrapped content travels with the page until it reaches its offset, then stays put while the page moves on. The semantics are plain `position: sticky` — pinning is relative to the nearest *scrolling* ancestor, so the element works inside a scrollable panel exactly as it does on the page itself, and a parent with `overflow: hidden` clips the pin. Both offsets may be given: the content then holds its place inside that band.