ock;
  width: 40px;
  height: 50px;
}

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

<p>Test passes if there is a filled green square and <strong>no red</strong>.</p>

<div id="reference-overlapped-red"></div>

<div style="display: flex; flex-direction: column; width: 100px; background: green;">
  <!-- 21px makes the inline-blocks wrap -->
  <div style="margin-right: 21px; flex: 0 0 auto; line-height: 0px;">
    <div cl