body { 
     background-color: #efefef;
     background-image:url(https://img2018.cnblogs.com/blog/1534387/201907/1534387-20190714090721673-2021235032.png); 
    // background-image:url(https://random.52ecy.cn/randbg.php); 
     background-repeat: no-repeat; 
     background-attachment: fixed; 
     background-position: center 0; 
     background-size: cover; 
    padding-top:0px;
  }