* {
	box-sizing: -webkit-border-box;
	box-sizing: -moz-border-box;
	box-sizing: border-box;
}

.container {
	width:600px;
	background-color: gray;
}

aside, .primary-content{
	height: 400px;
}
aside {
	width: 30%;
	background-color: red;
        float: left;
}
.primary-content {
	width: 70%;
	background-color: blue;
        float: right;
}