#Container {
    width: 50%;
    margin: auto;
    overflow: hidden;
    position: relative;
}

#A {
    width: 15%;
    float: left;
    text-align: right;
    background-color: red;
    margin-bottom: -99999px;
    padding-bottom: 99999px;
}

#B {
    width: 70%;
    float: left;
    text-align: center;
    background-color: aqua;
    margin-bottom: -99999px;
    padding-bottom: 99999px;

}

#C {
    width: 15%;
    float: left;
    text-align: left;
    background-color: yellow;
    margin-bottom: -99999px;
    padding-bottom: 99999px;
}