body{
    background-image: url(https://images.cnblogs.com/cnblogs_com/duidui-li/1768571/o_2005190758223.jpeg);
    background-position: initial;
    background-size: cover;
    background-repeat: no-repeat;
    background-attachment: fixed;
    background-origin: initial;
    background-clip: initial;
    height:100%;
    width:100%;
    }