.container {
	box-shadow: 0 0 5px rgba(0,0,0,0.5);
	width: 50%;
	margin: 0 auto;
	padding: 15px;
}

.article {
	float: left;
	width: calc(100% / 3);
	padding: 0 15px;
	box-sizing: border-box;
}

.clearfix:after {
	content: "";
	display: block;
	clear: both;
}