i new to HTML, etc and im having a problem im making javascript drop down boxes using tables and i cant get the code to go right with my css,

Code:
<html>
<head>
<!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" xml:lang="en" lang="en">

<head>

<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<link rel="stylesheet" href="http://www.gavssite.com/css/images/PixelGreen.css" type="text/css" />
<title>##########</title>
<style>
body{font-family:arial;}

a{color:black;text-decoration:none;font:bold}

table.menu
{
font-size:100&#37;;
position: absolute;
float: left;
visibility:hidden;
}
</style>
<script type="text/javascript">
function showmenu(elmnt)
{
document.getElementById(elmnt).style.visibility="visible"
}
function hidemenu(elmnt)
{
document.getElementById(elmnt).style.visibility="hidden"
}
</script>
	</head>
<body>


<div id="wrap">

	<div id="header"><div id="header-content">	
		
		<h1 id="logo"><a href="index.html" title="">Gav's<span class="gray"> Site</span></a></h1>	
		<h2 id="slogan">Everything You Need Here</h2>		
		
		<!-- Menu Tabs -->
		<ul>
			<li><a href="http://www.gavssite.com/index.html" >Home</a></li>
			<li><table width="auto" border="0">
 
  <td onmouseover="showmenu('tutorials')" onmouseout="hidemenu('tutorials')">
   <a href="/default.asp">Downloads</a><br />
   <table class="menu" id="tutorials" width="auto">
   <tr border="0"><td class="menu"><a href="/html/default.asp">Mac</a></td></tr>
   <tr><td class="menu"><a href="/xhtml/default.asp">Windows</a></td></tr>
   <tr><td class="menu"><a href="/css/default.asp">Linux</a></td></tr>

   </table>
  </td>
  </td>
 </tr>
</table></li>
			<li><a href="games.html">Games</a></li>
			<li><a href="forum.html">Forum</a></li>		
			<li><a href="homelinks.html">Homelinks</a></li>
			<li><a href="links.html">Ad's Blast</a></li>	
			<li><a href="links.html">About</a></li>		
						
		</ul>		
		






	
	
	</div></div>


</body>
</html>
ok the tag now does this



and without hover over on



can anyone help me get it like this, i want it show it drops down when you hover over it and it looks just the same as the rest of the nav bar any help will be help


heres a link to my css just in case, http://www.gavssite.com/css/images/PixelGreen.css


Thanks