hi people,

just a quick question. i have this code from internet to display a menu but i want to add a 3rd level menu... how do i make it please???

Code:
#navigation {
	margin:0;
	padding: 0;
	clear:both;
	width:500px;
	height:51px;
	background: #d6eaf8 url(images/dropdown-bg.gif) repeat-x left top;
}


ul.nav-main,
ul.nav-main li {
	list-style: none;
	margin: 0;
	padding: 0;
}


ul.nav-main {
	position: relative;
	z-index: 597;
}

ul.nav-main li:hover > ul {
	visibility: visible;
}


ul.nav-main li.hover,
ul.nav-main li:hover {
	position: relative;
	z-index: 599;
	cursor: pointer;
	background: url(images/dropdown-bg-hover.gif) repeat-x left top;
}



ul.nav-main li {
	float:left;
	display:block;
	height: 51px;
	color: #999;
	font: 14px Arial, Helvetica, sans-serif;
	background: url(images/separator.gif) no-repeat right center;
}

ul.nav-main li a {
	display:block;
	padding: 16px 16px 0 16px;
	height: 35px;
	color: #FFF;
	font: 14px Arial, Helvetica, sans-serif;
	text-decoration:none;
}

ul.nav-main li a:hover {
	color:#FFFFFF;
}



ul.nav-main *.list {
	background: url(images/navigation-arrow.gif) no-repeat right top;
}



ul.nav-sub {
	visibility: hidden;
	position: absolute;
	padding:10px;
	top: 48px;
	left: 0;
	z-index: 598;
	background: #353535;
	border-right: 1px solid #000;
	border-bottom: 1px solid #000;
	border-left: 1px solid #000;
}


ul.nav-sub li {
	list-style:none;
	display:block;
	padding: 0;
	height: 27px;
	float: none;
	width:145px;
	border-bottom: 1px solid #5a5a5a;
	background: none;
}

ul.nav-sub li a {
	list-style:none;
	display:block;
        color: #FFF;
	padding: 6px 5px 6px 5px;
	height: 15px;
	float: none;
	width:145px;
	background: none;
	font: 12px Arial, Helvetica, sans-serif;	
}
Thanks:
Duarte V.