<!DOCTYPE html> <meta charset="utf-8"> <title>CSS Test: A Web Animations on ::backdrop</title> <link rel="help" href="https://fullscreen.spec.whatwg.org/#::backdrop-pseudo-element"> <link rel="match" href="backdrop-animate-002-ref.html"> <dialog id="target">Dialog contents</dialog> <!-- This test fails on WPT.fyi with off-by-one on the green background (Chrome-only): --> <meta name="fuzzy" content="maxDifference=0-1;totalPixels=0-472500"> <script> const target = document.getElementById("target"); target.showModal(); target.animate({ opacity: [0.1, 0.1], backgroundColor: ["green", "green"] }, { pseudoElement: "::backdrop", duration: Infinity }); </script>