chromium/third_party/blink/web_tests/external/wpt/css/css-conditional/container-queries/pseudo-elements-013.html

<!doctype html>
<title>@container: originating element container for highlight pseudo elements</title>
<link rel="help" href="https://drafts.csswg.org/css-conditional-5/#container-queries">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="support/cq-testcommon.js"></script>
<style>
  #target { container-type: inline-size; }
  #target::highlight(foo) {
    text-decoration-line: underline;
    text-decoration-thickness: 0px;
  }
  @container (width >= 300px) {
    #target::highlight(foo) {
      text-decoration-line: underline;
      text-decoration-thickness: 10cqw;
    }
    #target::highlight(bar) {
      text-decoration-line: underline;
      text-decoration-thickness: 10cqw;
    }
  }
</style>
<div id="outer" style="width: 200px">
  <div id="target"></div>
</div>
<script>
  setup(() => assert_implements_container_queries());

  test(() => {
    assert_equals(getComputedStyle(target, "::highlight(foo)").textDecorationThickness, "0px");
  }, `Initial text-decoration-thickness for highlight pseudo`);

  outer.style.width = "300px";

  test(() => {
    assert_equals(getComputedStyle(target, "::highlight(foo)").textDecorationThickness, "30px");
  }, `text-decoration-thickness for highlight pseudo depending on container`);
  test(() => {
    assert_equals(getComputedStyle(target, "::highlight(bar)").textDecorationThickness, "30px");
  }, `text-decoration-thickness for highlight pseudo depending on container only defined in a query`);
</script>