nav > ul > li {
    width: 16.66666667%;
    float: left;
}
nav > ul,
article {
    overflow: auto;
}
article > div,
article > aside {
    float:left;
}
article > div {
    width: 66.666667%;
}
article > aside {
    width: 33.333333%;
}

footer {
    clear: left;
}