css/css-nesting/invalidation-003.html

<!doctype html>
<title>CSS Selectors nested invalidation with :has()</title>
<link rel="author" title="Steinar H. Gunderson" href="mailto:sesse@chromium.org">
<link rel="help" href="https://drafts.csswg.org/css-nesting-1/">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>

<style>
  .a {
    color: red;
    :has(&) {
      color: green;
    }
  }
</style>

<div id="container">
  Test passes if color is green.
  <div>
    <div id="child"></div>
  </div>
</div>

<script>
  test(() => {
    let container = document.getElementById('container');
    let child = document.getElementById('child');
    assert_equals(getComputedStyle(container).color, 'rgb(0, 0, 0)');
    assert_equals(getComputedStyle(child).color, 'rgb(0, 0, 0)');
    child.classList.add('a');
    assert_equals(getComputedStyle(container).color, 'rgb(0, 128, 0)');
    assert_equals(getComputedStyle(child).color, 'rgb(255, 0, 0)');
  });
</script>