xhtml/css-conditional-3.xhtml

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" lang="ja">
<head>
<meta charset="utf-8" />
<title>CSS Conditional Rules Level 3</title>
<style>
.OK {
  visibility: hidden;
}

@supports (margin: 0) {
  #at-supports .OK {
    visibility: visible;
  }
}
</style>
</head>
<body>
  <h1>CSS Conditional Rules Level 3</h1>
  <section id="at-supports">
    <h2>@supports ルール</h2>
    <ul>
      <li><span class="OK">OK</span></li>
    </ul>
  </section>
</body>
</html>