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

<!doctype html>
<title>CSS Container Queries Test: ::backdrop disappearing conditionally on dialog 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 {
    /* Prevent multiple layout passes due to scrollbars */
    overflow: hidden;
    background: green;
  }
  dialog {
    container-type: size;
    width: 100px;
    height: 100px;
    visibility: hidden;
  }
  dialog::backdrop {
    display: block;
    background-color: red;
  }
  @container (width > 1px) {
    dialog::backdrop {
      display: none;
    }
  }
</style>
<dialog id="dialog"></dialog>
<script>
  dialog.showModal();
</script>