css/css-cascade/important-prop.html

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>CSS Cascade: Important vs. Animations</title>
  <link rel="author" title="David Burns" href="http://www.theautomatedtester.co.uk">
  <link rel="author" title="Elika J. Etemad" href="http://fantasai.inkedblade.net/contact">
  <link rel="help" href="https://drafts.csswg.org/css-cascade/#importance">
  <link rel="match" href="important-prop-ref.html">
  <meta name="assert" content="Test passes if normal rules are overridden by animations, important rules override animations, and !important declarations are ignored in animations.">
  <style>
  @keyframes override {
    from, to {
      background: #f00; color: green;
      border-color: green; border-color: red !important;
    }
  }

  .square {
    color:#00f;
    animation: override 1s infinite;
    width: 80px;
    height: 80px;
    border: 10px solid red;
    text-align: center;
  }
  div {
    background-color:green !important;
    color: red;
  }
  </style>
</head>
<body>
  <p>Test passes if there is a filled green square and <strong>no red</strong>.</p>

  <div class="square green">FAIL</div>

</body>
</html>