<!doctype html>
<meta charset="utf-8">
<title>CSS Test Reference</title>
<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
<style>
div {
  width: calc(1ex + 1ch + 1em);
  height: calc(1ex + 1ch + 1em);
  background: green;
}
</style>
<div></div>
