body {
background: url("https://images.cnblogs.com/cnblogs_com/mh-blog/1853248/o_200923153841e844f36c8f859ca6e902b4fcc6be11ed.jpg") fixed;
font-family: sans-serif;
}

#home {
opacity: 0.9;
margin: 0 auto;
width: 75%;
margin-top: 30px;
margin-bottom: 50px;
}