body {
    color: #000;
    background-color: #e6e6e6;
    font-family: "Helvetica Neue",Helvetica,Verdana,Arial,sans-serif;
    font-size: 12px;
    min-height: 101%;
    background: url(https://images.cnblogs.com/cnblogs_com/021700613h/1642798/o_200206062617IMG_20180630_090505R.jpg) fixed;
    opacity: 0.8;
}