canvas {
    /* display: block; */
    position: fixed;
}
#home h1 {
    font-size: 45px;
}

body {
    background-image: url("https://images.cnblogs.com/cnblogs_com/blogs/764796/galleries/2213334/o_220905085746_background.jpeg");
    background-position: initial;
    background-size: cover;
    background-repeat: no-repeat;
    background-attachment: fixed;
    background-origin: initial;
    background-clip: initial;
    height: 100%;
    width: 100%;
    overflow-x: hidden;
}

#home {
    opacity: 0.7;
}

.wall {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
}


div#top {
    background: url("https://images.cnblogs.com/cnblogs_com/blogs/764796/galleries/2213334/o_220905085756_background-1.png");
    z-index: -4;
    -webkit-animation: da 200s linear infinite;
    -o-animation: da 200s linear infinite;
    animation: da 200s linear infinite;
}

@keyframes da {
    0% {
        background-position: 0 0;
    }

    100% {
        background-position: 0 600%;
    }
}

@-webkit-keyframes da {
    0% {
        background-position: 0 0;
    }

    100% {
        background-position: 0 600%;
    }
}

@-moz-keyframes da {
    0% {
        background-position: 0 0;
    }

    100% {
        background-position: 0 600%;
    }
}

@-ms-keyframes da {
    0% {
        background-position: 0 0;
    }

    100% {
        background-position: 0 600%;
    }
}