chromium/third_party/blink/web_tests/external/wpt/css/css-conditional/container-queries/top-layer-dialog-backdrop.html

<!doctype html>
<title>CSS Container Queries Test: ::backdrop depending on @container</title>
<link rel="help" href="https://drafts.csswg.org/css-conditional-5/#container-queries">
<link rel="match" href="top-layer-dialog-backdrop-ref.html">
<style>
  html { background: green; }
  #container { container-type: inline-size; }
  @container (max-width: 200px) {
    ::backdrop { display: none; }
    #dialog { visibility: hidden; }
  }
</style>
<div id="container">
  <dialog id="dialog"></dialog>
</div>
<script>
  dialog.showModal();
  dialog.offsetTop;
  container.style.width = "100px";
</script>