body {

    background: url(https://images.cnblogs.com/cnblogs_com/chen-tian-yuan/1516454/o_AS.jpg) fixed;
}    
#home {
margin: 0 auto;
opacity: 0.8;
width: 75%;
min-width: 1080px;
background-color: #fff;
padding: 30px;
margin-top: 50px;
margin-bottom: 50px;
box-shadow: 0 2px 6px rgba(100, 100, 100, 0.3);
}