css/css-transforms/perspective-zero.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Test: transform: perspective(0)</title>
<link rel="author" title="Xidorn Quan" href="https://www.upsuper.org">
<link rel="author" title="Mozilla" href="https://www.mozilla.org">
<link rel="author" title="L. David Baron" href="https://dbaron.org/">
<link rel="author" title="Google" href="http://www.google.com/">
<link rel="help" href="https://drafts.csswg.org/css-transforms-2/#funcdef-perspective">
<link rel="help" href="https://github.com/w3c/csswg-drafts/issues/413">
<meta name="assert" content="perspective(0) should be clamped to 1px">
<link rel="match" href="reference/green.html">
<style>
#cover-me {
  width: 100px;
  height: 100px;
  background: red;
  position: relative;
  margin-bottom: -100px;
}
#test {
  background: green;
  transform-origin: top left;
  width: 50px;
  height: 50px;
  /* perspective(0) should be treated as perspective(1px), which should
   * cause this box to be much larger. */
  transform: perspective(0) translateZ(0.5px);
}
</style>
<p>Pass if there is NO red below:</p>
<div id="cover-me"></div><div id="test"></div>