Horizontal menu problem

[elite311]

Hi I have been trying to get my horizontal menu to work proporly but can't seem to figure out what I'm missing. I'm just trying to make it have a thick border when you hover over it but cant seem to make it work. Could someone tell me what I'm missing here?

Thanks

.horznav{
font-weight: normal;
width: 100%;
}

.horznav ul{
padding: 12px 0 7px 0;
margin: 0;
text-align: center;
}

.horznav ul li{
display: inline;
}

.horznav ul li a{
	color: #0099CC;
	padding: 12px 3px 4px 3px; 
	margin-right: 20px; 
	text-decoration: none;
	text-transform: none;
}

.horznav ul li a:hover{
	border-bottom-color: #000066;
	border-bottom-width: 3px;
	border-bottom-style: solid;
}

[elite311]

I can make it work if i add the folowing to my css but i messes up all my formating.. any idea?

.horznav ul li a{
	color: #0099CC;
	padding: 12px 3px 4px 3px;
	margin-right: 20px;
	text-decoration: none;
	text-transform: none;
	font-family: "Arial Rounded MT Bold";
	font-size: 14px;
	float: left;