body {
    background-color:gray;
}
#container {
    width:960px;
    height:500px;
    margin-left:auto;
    margin-right:auto;
    border:1px solid red;
}
#outer_left {
    float:left;
    margin:15px;
    width:70%;
    height:400px;
    margin-left:auto;
    margin-right:auto;    
    background-color:black;
}
.inner_left {
    top:20px;
    margin:10px;
    width:68%;
    height:23%;
    position:relative;

    background-color:blue;
}
#outer_right {
    margin:15px 15px 15px 0px;
    float:right;
    width:25%;
    height:400px;
    background-color:black;
}