<!DOCTYPE html>
<html>
 <head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
  <title>Letter spacing with surrogate characters</title>
   <style type="text/css">
    p { letter-spacing: 10px; }
   </style>
 </head>
 <body>
  <!-- ASCII for sanity check -->
  <p>AAAAAA</p>
  <!-- SMP Characters, MATHEMATICAL BOLD CAPITAL A. It will probably appear as hexboxes, but that doesn't matter -->
  <p>&#x1d400;&#x1d400;&#x1d400;&#x1d400;&#x1d400;&#x1d400;</p>
 </body>
</html>