Frontend & browser·Layout, CSS and the cascade
the page scrolls, but your scroll listener on `window` never fires because the scrolling happens inside a div.
Scroll container
Also calledoverflow container, scroll port
Any element whose `overflow` is scroll or auto, which creates its own scrolling region with its own scroll position and scroll events. Introducing one breaks anything that assumed the document scrolls: sticky elements, scroll listeners, IntersectionObserver defaults and scroll restoration all bind to the wrong thing. Nested scroll containers are worse still, because scroll chaining decides which one moves and users rarely agree with the answer.