body{   font-size: 15px;
    padding: 0;
    margin: 0;
    font-family: "Courier New","Courier New",Courier New;
    //background: url(https://images.cnblogs.com/cnblogs_com/TheRoadToTheGold/979363/o_2011.1.3_1920x1200.jpg) no-repeat top center fixed;
    background-color:#f5f5d5;
    min-width: 1200px;
    background-size: cover;
    opacity: 0.8;
}