body {
    background-image: url("https://images.cnblogs.com/cnblogs_com/blogs/697965/galleries/2016958/o_21081906563520200510171831_unaWh.jpeg");
    background-color: white;
    background-position: center;
    background-size: 75%;
    background-repeat: no-repeat;
    background-attachment: fixed;
}

#home{
    background:rgba(255,255,255,0.85);
}