<!DOCTYPE html>
<html>
  <head>
    <title>default font</title>
    <meta charset="utf-8"/>
  </head>
  <body style="font: 20px monospace;">

    <!-- font.minimum-size.x-math set to 40 -->
    <math>
      <mn>x-math language</mn>
    </math>

  </body>
</html>