<html>
 <head>
  <title>Negative Line Height</title>
  <style type="text/css">

    div#test1 {font: normal 10px/1 Helvetica, Arial, sans-serif; font: normal 50px/-2 Helvetica, Arial, sans-serif;}

    div#test2 {position: absolute; width: 200px; margin: 1em 0 0; line-height: 3em; background: red;}
    div#test2 span {display: block; position: absolute; left: 0; top: 0; width: 200px; line-height: 3em; line-height: -5em; background: green;}

  </style>
 </head>
 <body>

  <div id="test1">This should be fairly small text, rather than huge.</div>

  <div id="test2">&nbsp;<span>There should be no red here</span></div>

 </body>
</html>