<!DOCTYPE html>
<title>CSS Cascade: 'revert' keyword in keyframe animations</title>
<link rel="help" href="https://drafts.csswg.org/css-cascade/#default">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
  @keyframes test {
    from { margin-top: 0px; }
    50% { margin-top: revert; }
    to { margin-top: 0px; }
  }
  #h1 {
    margin-top: 0px;
    animation: test linear 1000s -500s;
  }
</style>
<h1 id=h1></h1>
<h1 id=ref></h1>
<script>
  test(function() {
    let actual = getComputedStyle(h1).marginTop;
    let expected = getComputedStyle(ref).marginTop;
    // This test assumes that the UA style sheet sets a non-0px value on
    // <h1> elements:
    assert_not_equals(expected, '0px');
    assert_equals(actual, expected);
  }, 'The revert keyword works with @keyframes');
</script>