html {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%
}

body {
    width: 100%;
    height: 100%;
    margin: 0;
    overflow: hidden;
    background: #f4f4f4
}

.scrollBox {
    width: calc(50% - 20px);
    float: left;
    border: 1px solid #e8e8e8;
    background: #fff;
    box-sizing: border-box;
    margin: 10px 0 10px 10px;
    height: calc(50% - 15px);
    overflow: auto;
    padding: 10px
}

.scrollBox:nth-of-type(2n) {
    margin-right: 10px
}

.scrollBox:nth-of-type(3),
.scrollBox:nth-of-type(4) {
    margin-top: 0
}

.contentBox1 {
    width: 100%;
    height: 900px;
    background-image: url(../images/1.png);
    background-size: cover;
    background-repeat: no-repeat
}

.contentBox2 {
    width: 1200px;
    height: 100%;
    background-image: url(../images/2.png);
    background-size: cover;
    background-repeat: no-repeat
}

.contentBox3 {
    width: 1200px;
    height: 900px;
    background-image: url(../images/2.png);
    background-size: cover;
    background-repeat: no-repeat
}