css/css-fonts/system-ui.html

<!doctype html>
<title>Tests that system-ui font-family works</title>
<link rel="help" href="https://drafts.csswg.org/css-fonts/#system-ui-def">
<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
<link rel="author" title="Mozilla" href="https://mozilla.org">
<link rel="mismatch" href="system-ui-notref.html">
<link rel="stylesheet" href="/fonts/ahem.css">
<style>
p {
  font-family: system-ui, Ahem;
}
</style>
<p>ABC</p>