#container-a {
    width: 450px;
    background-color: red;
    font-size: 22px;
}

#container-b {
    width: 500px;
    background-color: blue;
    font-size: 22px;
}

#container-h {
    width: 100%;
    height: 70px;
    vertical-align: text-top;
    background-color: green;
    font-size: 22px;
}