#nav{
			width: 600px;
			margin-left:auto;
			margin-right:auto;
		}
		#nav a {
			display: block;
			background-color:#c9c9c9;
			width:200px;
			text-align: center;
			text-decoration: none;
			float: left; 

		}
		#nav a:hover {
			background-color:  #a6a6a6;
			border-bottom:5px blue solid;
		}
		#nav .active{
			border-bottom:5px blue solid;
		}