css/css-flexbox/percentage-heights-006.html

<!DOCTYPE html>
<title>Definite cross sizes</title>
<link rel="author" title="David Grogan" href="mailto:dgrogan@chromium.org">
<link rel="help" href="https://drafts.csswg.org/css-flexbox-1/#definite-sizes">
<link rel="match" href="../reference/ref-filled-green-100px-square.xht" />
<meta name="assert" content="In a column flexbox, the height of a fully inflexible item with fixed flex-basis is definite, and percent children resolve against the flex basis, not the specified height." />

<style>
x-flexbox {
  display: flex;
  flex-direction: column;
}

x-item {
  height: 0px;
  flex: 0 0 100px;
}

x-item>div {
  width: 100px;
  height: 100%;
  background: green;
}

#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>

<x-flexbox>
  <x-item>
    <div></div>
  </x-item>
</x-flexbox>