#principal{
		margin: 0;
        padding: 0;
		list-style-type: none;
	}
#principal li {
		list-style-type: none;
		float:left;
	}
#principal a {
		margin:3px;
		text-decoration: none;
        color: #ffffff;
        background-image:url(cnormal.png);
        padding:5.7px 9.8px 5.7px 9.8px;
        display: block;
		font-family:arial;
		font-size:12;
		font-weight:bold;
	}
#principal a:hover{
		background-image:url(cover.png);
		color:#000000;
	}