ok scusate pensavo ci fossero dei motivi di base 
essendo una cosa visibile soltanto a chi si registra, vi posto qui il codice completo (anche gli altri css)
codice:
<html>
<head>
<link rel=stylesheet href="../style.css" type="text/css">
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<meta http-equiv="Content-Language" content="en,it">
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="description" content="My website">
<meta name="keywords" content="..................................">
<META NAME="revisit-after" content="2 days">
<title>My Website </title>
</head>
<style type="text/css">
body{
margin: 0;
padding: 0;
border: 0;
overflow: auto;
}
#framecontent{
top: 0;
left: 0;
width: 100%;
height: 40px; /*Height of frame div*/
background-color: #0054FF;
color: white;
}
#maincontent {
top: 39px; /*Set top value to HeightOfFrameDiv*/
left: 0;
right: 0;
bottom: 0;
}
table.big th, table.big td {
border-width: 1px;
padding: 5px;
border-style: solid;
border-color: #B3B3B3;
background-color: white;
-moz-border-radius: ;
font-size : 11px;
font-family : Verdana,Helvetica,Arial,sans-serif;
}
table.topframe th, table.topframe td {
background-color: #0054FF;
font-size : 14px;
font-family : Verdana,Helvetica,Arial,sans-serif;
color: white;
}
table.main th, table.main td {
font-size : 11px;
font-family : Verdana,Helvetica,Arial,sans-serif;
}
table.account th, table.account td {
font-size : 11px;
font-family : Verdana,Helvetica,Arial,sans-serif;
border-width: 0px;
padding: 5px;
border-style: solid;
border-color: white;
}
table.mex th, table.mex td {
font-size : 11px;
font-family : Verdana,Helvetica,Arial,sans-serif;
border-width: 0px;
padding: 5px;
border-style: solid;
border-color: white;
border-collapse:collapse
}
.privatem{
font-size : 11px;
font-family : Verdana,Helvetica,Arial,sans-serif;
cursor:pointer;
border:outset 1px #ccc;
background:#999;
color:#666;
width:200px;
font-weight:bold;
padding-top:0px;
padding-left:5px;
padding-right:5px;
padding-bottom:0px;
background:url(formbg.gif) repeat-x left top;
}
a.basic:link {color:#324C82;text-decoration:none;}
a.basic:visited {color:#324C82;text-decoration:none;}
a.basic:hover {color:#324C82;text-decoration:underline;}
a.basic:active {color:#324C82;text-decoration:underline;}
a.pageuser:link {color:#2300FF; font-weight:bold; text-decoration:none;}
a.pageuser:visited {color:#2300FF; font-weight:bold; text-decoration:none;}
a.pageuser:hover {color:#2300FF; font-weight:bold; text-decoration:underline;}
a.pageuser:active {color:#2300FF; font-weight:bold; text-decoration:underline;}
</style>
<style type="text/css">
div.shortmenu {
padding-top:3px;
padding-bottom:3px;
background-color:#F2F2F2;
}
div.listmenu {
padding-top:5px;
line-height:160%;
}
div.replies {
padding-left:60px;
}
div.topframe {
padding-top:10px;
padding-left:2px;
}
div.mainmex {
padding-top:7px;
padding-bottom:7px;
font-size : 13px;
font-family : Verdana,Helvetica,Arial,sans-serif;
</style>
<style type="text/css">
input.btn {
cursor:pointer;
color:white;
font: bold 100% Verdana,Helvetica,Arial,sans-serif;
background-color:#4E79D7;
border:1px solid;
border-color: #314C87 #314C87 #314C87 #314C87;
padding-top:2px;
padding-bottom:2px;
padding-left:2px;
padding-right:2px;
padding:2px;
</style>
<link rel="stylesheet" type="text/css" href="menu/menu-dd.css">
<style type="text/css">
html,body{margin:0;padding:0}
body{background:#FFF;color:#333}
div#container{width:850px;margin:0 auto;background: #3B5998;color:#fff}
</style>
<body>
<div id="framecontent">
<script language="JavaScript">
var larghezza=window.screen.width;
if (larghezza>1024)
{
larg_px="1024px";
}
else
{
larg_px="100%";
}
document.write('<center><table class="topframe" width="'+larg_px+'" border="0" cellspacing="0" cellpadding="0" nowrap>');
</script>
<noscript>
<center><table class="topframe" width='100%' border='0' cellspacing="0" cellpadding="0" nowrap>
</noscript>
<tr>
<td valign="top">
<div class='topframe'>
<div id="container">
<ul id="nav">
[*]
Home
[*]
Mail
<ul>
[*]Compose mail
<li class="sep">Inbox<span></span>
[*]Sent mail
[*]Spam
[/list]
[*]
Settings
<ul>
<li class="icon settings">Account settings
<li class="icon privacy">Privacy settings
[/list]
[/list]
</div>
grazie per l'aiuto