Read Bar
Real version: animation-timeline: scroll(root). Zero JavaScript, runs off the main thread.
Usage
Meant for
Examples
On a Mobile Nav
The scroll-progress strip under the top bar. The real version is one line — animation-timeline: scroll(root), no JavaScript — and the class switches to it with data-wm-scroll wherever the browser supports it. Here it runs on a timer so it is visible without scrolling.
The class is wm wm-read-bar — the first half is the marker the trigger and reduced-motion rules hook into, the second is the effect.