Menu Displaced only in Firefox

Hello,

When you visit this site http://www.sexinthecityparties.com

the "Contact" header in the menu is displaced only when viewing the page with Firefox.

Could someone please tell me what's wrong?

thanks
Andy

The code is called in header.php


<ul class="solidblockmenu">
<?php displayMenu(3); ?>
</ul>
<br style="clear: left" />


and the CSS is:



.solidblockmenu{
margin: 0;
padding: 0;
float: left;
color: #ad0000;
font-weight:normal;
font-style: 13px;
font-family:"Segoe UI",Calibri,"Myriad Pro",Myriad,"Trebuchet MS",Helvetica,Arial,sans-serif;
width: 100%;
overflow: hidden;
margin-bottom: 1em;
border: solid #141414;
border-width: 0px 0px 1px 0px;
background: black url(http://www.sexinthecityparties.com/images/blockdefault.png) center center repeat-x;
}

.solidblockmenu li{
display: inline;
}

.solidblockmenu li a{
float: left;
color: white;
padding: 2px 14px;
text-decoration: none;
border-right: 0px solid #141414;
}

.solidblockmenu li a:visited{
color: white;
}

.solidblockmenu li a:hover, .solidblockmenu li .current{
color: white;
background: transparent url(http://www.sexinthecityparties.com/images/blockactive.gif) center center repeat-x;
}

In http://www.sexinthecityparties.com/wp-content/themes/mystique/style.css

on line 83 find this
ul li, ol li {
list-style-position: outside;
margin-left: 2.5em;
}

Remove or lessen the margin-left: 2.5em;

Removing makes the bottom of the menu shorter, but I see no other problems.

perfect that actually worked!! you are a star!!