body {
    color: #000;
    background: url(https://images.cnblogs.com/cnblogs_com/yinwenbin/1956785/o_210404054931ChMkJ1bKxEKIV_XtAAMDRPPbKYsAALHEADKINsAAwNc636.jpg) fixed;
    background-size: 100% 100%;
    background-repeat: no-repeat;
    font-family: "Helvetica Neue",Helvetica,Verdana,Arial,sans-serif;
    font-size: 12px;
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}