css/css-fonts/first-available-font-001.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS-fonts: first available font and the ex unit</title>
<link rel="author" title="Florian Rivoal" href="https://florian.rivoal.net">
<link rel="help" href="https://drafts.csswg.org/css-fonts-3/#first-available-font">
<link rel="help" href="https://drafts.csswg.org/css-fonts-4/#first-available-font">
<link rel="match" href="first-available-font-001-ref.html">
<meta name="assert" content="Fonts that do not include the U+0020 character are not considered the first available font (used to determine the ex unit), even when at the start of the font list.">
<style>
/* Two arbitrary fonts with different metrics */
@font-face {
  font-family: 'A-no-space';
  font-style: normal;
  font-weight: 400;
  src:  url(/fonts/Revalia.woff) format('woff');
  unicode-range: U+0061; /* Not including U+0020, so it cannot be the first available font*/
}
@font-face {
  font-family: 'B';
  font-style: normal;
  font-weight: 400;
  src: url(/fonts/AD.woff) format('woff');
}

div {
  width: 1ex;
  height: 0.5ex;

  font-size: 200px;
  background: blue;
  position: absolute;
}
#t1 { font-family: 'B', sans-serif; margin-top: 0.5ex; } /* half a square, shifted down */
#t2 { font-family: 'A-no-space', 'B', monospace; } /* Should use B as the first available font, and therefore be the same size as t1 */

/* Both elements are using different generic fallback fonts, so that they end up being sized differently if web-fonts fail to load. */

</style>

<p>Test passes if there is <strong>a blue square</strong> below.

<div id=t1></div>
<div id=t2></div>