<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="it">
<head>
<title></title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"/>
<style type="text/css">
<!--
body{
font-size:100%;
font-family:Verdana, Helvetica, sans-serif;
}
.xx-small{font-size:0.55em;}
.x-small{font-size:0.60em;}
.small{font-size:0.80em;}
.medium{font-size:1em;}
.large{font-size:1.20em;}
.x-large{font-size:1.55em;}
.xx-large{font-size:1.80em;}
-->
</style>
</head>

<body>
<div class="xx-small">

prova paragrafo</p></div>
<div class="x-small">

prova paragrafo</p></div>
<div class="small">

prova paragrafo</p></div>
<div class="medium">

prova paragrafo</p></div>
<div class="large">

prova paragrafo</p></div>
<div class="x-large">

prova paragrafo</p></div>
<div class="xx-large">

prova paragrafo</p></div>
</body>
</html>

così va, controlla i collegamenti con il css
ciao paolo