+−<!doctype html> +−<title>CSS Test reference</title> +−<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io"> +−<style> +−:root { +− font-size: 2em; +−} +− +−div { +− width: 10rem; +− height: 10rem; +− background: green; +−} +−</style> +−<div></div>