#home h1{
    font-size:45px;
}
body{
background-image: url("https://images.cnblogs.com/cnblogs_com/hmm01031007/1617523/o_19122007571622.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:0.83;
}
.wall{
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
}