.back-up{
	position: fixed;
	bottom: 0px;
	right: 30%;
}
       
@media screen and (max-width: 768px) {
	.back-up{
		position: fixed;
		bottom: 0px;
		right: 20%;
	}
}

.back-up a{
	display: block;
	width:50px;
	height: 50px;
	background:rgb(255, 102, 0);
	opacity: .1;
	font-size: 20px;
	color: #fff;
	text-align: center;
	text-decoration: none;
	border-radius: 10px 10px 0 0;
	transition: 1s;
}
.back-up a:hover{
  transform:rotate(360deg);
  opacity: 0.7;
}
 #Title{
      	position: relative;
      	z-index: 99;
      }
      #Title::after{
        content:"";
        width: 200px;
        height:200px;
        background: url(https://files.cnblogs.com/files/fanglylu/hello.gif);
        position: absolute;
        left:-200px;
        top: -100px;
        display: none;
      } 
    #Title:hover::after{
   	  display: block;
    }
  #main{ z-index: 9;}