
  #reference-overlapped-red {
    position: absolute;
    background-color: red;
    width: 100px;
    height: 100px;
    z-index: -1;
  }

  #constrained-grid {
    display: grid;
    width: 10px;
    height: 10px;
  }

  #test-grid-item-overlapping-green {
    background-color: green;
    width: 100px;
    height: 100px;
  }

  #content-500x500 {
    width: 500px;
    height: 500px;
  }
</style>
<p>Test passes if there is a filled green square and <strong>no red</strong>.</p>

<div id="reference-overlapp