css/css-values/reference/ex-unit-001-ref.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Test Reference</title>
<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
<meta name="flags" content="ahem">
<link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
<style>
  @font-face {
    font-family: foo;
    font-weight: 900;
    src: url('/fonts/noto/noto-sans-v8-latin-regular.woff');
  }
  div {
    font-family: foo, sans-serif;
    font-weight: 900;
    width: 10ex;
    height: 20px;
    background: blue;
    margin: 20px;
    font-size: 20px;
  }
</style>
<p>All lines except the first should be the same length</p>
<div style="font-family: Ahem; font-weight: normal;"></div>
<div></div>
<div></div>
<div></div>