Browser support
Animatio ships the bleeding edge and annotates it rather than withholding it. Every rule built on a not-yet-widely-supported feature carries a machine-readable @support-status comment that survives minification — so the answer is in the CSS you actually downloaded.
What your browser does
| Feature | Here | Used for |
|---|
The policy
Animatio targets the current and previous two versions of Chrome, Edge, Safari and Firefox, plus iOS Safari and Chrome Android. Everything outside that renders the baseline layer — ordinary CSS animation, always leaving content visible and readable.
No IE. No polyfills. No @supports around widely-available features.
The one thing that is gated
Rule §2.2 of the design: any rule that hides content lives inside @supports and nowhere else. That is a correctness rule, not caution about market share — opacity: 0 in a base scroll class means a permanently invisible page in Firefox stable.
The build proves it. dist/test/animatio.nosda.css rewrites every scroll-driven @supports condition to something guaranteed false, so any engine renders the fallback path, and the test suite asserts that nothing is hidden there. That is reproducible forever, unlike a browser flag whose name drifts.
The one thing that is broken, not unsupported
backdrop-filter: url(#svgFilter). WebKit parses it and renders nothing (bug 245510); Chromium handles only some cases.
@supports tests whether a declaration parses, not whether it renders, so the obvious guard returns true in Safari and switches the broken path on. It looks safe and is actively harmful. Refraction is therefore opt-in:
<html data-an-refract="on">Set it after your own render probe. If you would rather not run one, do not use refraction — an-glass already looks good.