A band whose mark is driven from JavaScript

No CSS animation, no CSS transition, no Web Animations API object. A requestAnimationFrame loop writes an inline transform, which is how GSAP, ScrollSmoother and every rig like them move a page.

A second band, still

Nothing here moves, so the census stays at one and the fixture tests the boundary rather than a landslide.

A third

The header is static too: this page has no escape into an abstention.