<!DOCTYPE html>
<meta charset="utf-8" />
<title>Zero sized element with sizable decendant</title>

<style>
  #parent { width: 0; height: 0; }
  #child { width: 100; height: 100; background-color: blue; }
</style>

<div id="parent">
  <div id="child">
    &nbsp;
  </div>
</div>