<div class="top"></div>
<div class="left"></div>
<div class="right"></div>
<div class="center"></div>

div {
    height: 200px;
}
.top {
    background-color: #aaaaaa;
    height: 100px;
    border-bottom: 2px solid white;
}

.left {
    background-color: red;
    width: 10%;
    float: left;
}
.right {
    background-color: blue;
    float: right;
    width: 10%;
}
.center {
    background-color: green;
    margin-left: 10%;
    margin-right: 10%;
    border-left: 2px solid white;
    border-right: 2px solid white;
}