body{
    font-family: YouYuan;
    background-image: url("https://images.cnblogs.com/cnblogs_com/blogs/783607/galleries/2275665/o_230216094901_background.jpg");
    background-attachment: fixed;
    background-repeat: no-repeat;
    background-size: cover;
}
#home{
    opacity: 0.9;
}