body {
    background-image: url(https://images.cnblogs.com/cnblogs_com/z-belief/1501688/o_o_preview.jpg);
    background-position: initial;
    background-size: cover;
    background-repeat: no-repeat;
    background-attachment: fixed;
    background-origin: initial;
    background-clip: initial;
    height: 100%;
    width: 100%;
}
#home{
    opacity:0.9;
}