<!DOCTYPE html>
<meta charset="utf-8">
<link rel="author" title="Martin Robinson" href="mailto:mrobinson@igalia.com">
<style>
  html, body { margin: 0; padding: 0 }
  #transformed {
    margin-left: 10px;
    margin-top: 10px;
    width: 200px;
    height: 200px;
    background: grey;
  }

  #fixed {
    width: 50px;
    height: 50px;
    background: green;
  }
</style>

<body>
    <div id="transformed">
        <div id="fixed"></div>
    </div>
  </body>
</html>
