/* The style of the active tab; it has a white background and white bottom border */
ul.tabbernav li.tabberactive a {
border-bottom:1px solid #FFFFFF;
}
/* The color of the tab names; it is lavender colored */
ul.tabbernav li a:link {
color:#444488;
}
/* Style of the tabs when you hover over them with your pointer; black font, with darker purple background except for the active tab */
ul.tabbernav li a:hover{
color: #000000;
background: #AAAAEE;
border-color: #222277;
}
ul.tabbernav li.tabberactive a:hover{
color: #000000;
background: white;
border-bottom: 1px solid white;
}
/* Style of the tab content; this is mostly the style of the gray border around the content */
.tabberlive .tabbertab {
border-color:-moz-use-text-color #AAAAAA #AAAAAA;
border-right:1px solid #AAAAAA;
border-style:none solid solid;
border-width:0 1px 1px;
padding:5px;
}
http://www.dynamicdrive.com/forums/archive/index.php/t-22199.html