<!doctype html>
<title>Test reference</title>
<link rel="stylesheet" href="/fonts/ahem.css">
<style>
  div {
    border: 1px solid black;
    line-height: 0;
  }
  span {
    font: 20px/1 Ahem;
    visibility: hidden;
  }
</style>
<div>
  <span>A</span>
</div>
