#principal li {
	display: inline;
	float: left;
	width: 170px;
	height: 180px;
	background-color: #e1e1e1;
	padding: 10px;
	margin: 10px;
	text-align: center;
	border-right: 1px solid #666666;
	border-bottom: 1px solid #666666;
}