<!DOCTYPE html>
<html>
 <head>
  <meta http-equiv="content-type" content="text/html; charset=utf-8">
 </head>
 <style>
   p { font-family: sans-serif; font-size: 24pt; }
   .small { font-size-adjust: 0.25; }
   .large { font-size-adjust: 0.9; }
 </style>
 <body>
   <p>hello</p>
   <p class="small">small</p>
   <p class="large">world</p>
 </body>
</html>