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

* {
    margin: 0;
}

html, body {
    background-color: #c0c0c0;
    height: 100%;
}

header, footer, section, div {
    border: solid;
    height: 25%;
}

section {
    width: 33.3333%;
    float: left;
}

div {
    width: 50%;
    float: left;
}

footer {
    clear: both;
}