body {
    color: #000;
    font-family: 'PingFang SC','Microsoft YaHei','Helvetica Neue','Helvetica','Arial',sans-serif;
    font-size: 13px;
    min-height: 101%;
    background: url(https://n.sinaimg.cn/sinakd10109/538/w500h838/20200408/7ca1-iryninw3714541.jpg);
}
#main{
    background: rgba(255, 255, 255, 0.15);
}
#mainContent{
    background: rgba(255, 255, 255, 0);
}