<!DOCTYPE html>
<html>
  <head>
    <title>-webkit-xxx-large font-size is identical to xxx-large value</title>
    <style>
      p {
        font-size: xxx-large;
      }
    </style>
  </head>
  <body>
    <p>This text should appear the same as text with font-size: xxx-large;</p>
  </body>
</html>