body {
color: #000;
opacity: 0.8;

background: url(https://images.cnblogs.com/cnblogs_com/popo33/1772643/o_200525022416guidao06.jpg) fixed;
background-size: 100%;
background-repeat: no-repeat;
font-family: "Helvetica Neue",Helvetica,Verdana,Arial,sans-serif;
font-size: 12px;
min-height: 101%;
}