Edit in JSFiddle

div {
    border : 1px solid #d3d3e3
}
#north {
    margin:0;
    padding:1em;
}
#south {
    margin:0;
    padding:1em;
}
#east {
    margin:0;
    padding:1em;
    width:6em;
    height:22em;
    float:left;
    margin-right:1.1em
}
#west {
    margin:0;
    padding:1em;
    width:6em;
    height:22em;
    float:right;
    margin-left:1.1em
}
#center {
    margin:0;
    padding:1em;
    padding-bottom:0em;
}
#center:after {
    content:' ';
    clear:both;
    display:block;
    height:0;
    overflow:hidden
}