<!DOCTYPE html>
<!--
 | This test ensures that a fixed position element forms a stacking context.
 | While this is not explicitly required in the spec, it matches the
 | functionality of Chrome, Firefox, Edge, and Safari (IE and old versions of
 | Opera do not treat it as a stacking context). The results should show the
 | blue box in front of the green box.
 |   https://www.w3.org/TR/CSS21/visuren.html#z-index
 -->
<html>
<head>
  <style>
    .fixed-container {
      position: fixed;

      width: 150px;
      height: 150px;

      background-color: rgb(158, 158, 158);
    }
    .green {
      position: absolute;

      left: 0px;
      top: 0px;

      width: 80px;
      height: 80px;

      z-index: 1;

      background-color: rgb(15, 157, 88);
    }
    .blue {
      position: absolute;

      left: 40px;
      top: 40px;

      width: 80px;
      height: 80px;

      background-color: rgb(66, 133, 244);
    }
  </style>
</head>
<body>
  <div class="fixed-container">
    <div class="green"></div>
  </div>
  <div class="blue"></div>
</body>
</html>