<!DOCTYPE HTML>
<html>
<head>
  <meta charset="utf-8">
  <title>CSS Reftest Reference</title>
  <link rel="author" title="Yusuf Sermet" href="mailto:ysermet@mozilla.com">
  <style>
    div {
      position: relative;
      width: 100px;
    }
    #div1,
    #div3 {
      background-color: #cfc;
      height: 100px;
    }
    #div1 {
      z-index: 5;
    }
    #div2 {
      display: contents;
      background-color: #fdd;
      height: 100px;
      top: -20px;
    }
    #div2_1 {
      background-color: #ffc;
      z-index: 6;
      top: -10px;
      height: 100px;
    }
    #div2_2 {
      z-index: 3;
      position: absolute;
      top: -15px;
      width: 40px;
      height: 300px;
      background-color: #ddf;
    }
    #div3 {
      z-index: 2;
      top: -50px;
    }
  </style>
</head>
<body>
  <div id="div1"></div>

  <div id="div2">
    <div id="div2_1"></div>

    <div id="div2_2"></div>
  </div>

  <div id="div3"></div>
</body>
</html>