#ul{
   width: 300px;
   position: absolute;
   margin-left: -150px;
   left: 50%;
}
#li{
	float: left;
	display: inline;
   	  }
a{
    display: block;
	width: 270px;
	height: 170px;	
	margin: 5px;
	text-align: center;
	font-family: 'Arial', Lucida Sans, sans-serif;
	line-height: 30px;
	color: #6699ff;
	border: none;
	background-color: #FFF;
	text-decoration: none;
padding: 10px 10px 30px 10px;
box-shadow: 0 3px 6px #666;
-webkit-box-shadow: 0 3px 6px #666;
}

a:after { content: attr(title); }

a:hover {
            font-weight: bold;            
					 }