<!doctype html>
<title>Container Relative Units: in @container prelude (dynamic)</title>
<link rel="help" href="https://drafts.csswg.org/css-contain-3/#container-lengths">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="support/cq-testcommon.js"></script>
<style>
  #outer {
     container-type: size;
     width: 40px;
     height: 40px;
   }
  #container {
    container-type: size;
    width: 16px;
    height: 16px;
  }

  @container ((width = 16px) and (width = 50cqw)) { #child { --cqw:true;  } }

</style>

<div id=outer>
  <div id=container>
    <div id=child>Test</div>
  </div>
</div>

<script>
  setup(() => assert_implements_container_queries());

  test(() => {
    assert_equals(getComputedStyle(child).getPropertyValue('--cqw'), '');
    outer.style.width = '32px';
    assert_equals(getComputedStyle(child).getPropertyValue('--cqw'), 'true');
  }, 'Query with container-relative units are responsive to changes');
</script>
