Css Dropdown Navigation zentrieren

[PhilippWien]

Hi, Ich versuche gerade vergebens die Suckerfish-CSS-Dropdown-Navigation zu zentrieren.~~~css #mainmenu
{
text-align: center;
width:100%;
height: 40px;
background-image: url(../images/navi.jpg) ;
background-repeat: repeat-x;

}
 #mainmenu ul {
height: 40px;
padding: 0;
margin: 0;

list-style: none;  

}

#mainmenu a {
display: block;
width: 70;
margin-top: 14px;

}

#mainmenu li {

float: left;  
width: 10em;  

list-style: none;

}