body{
    color:#000;
    background-color:#e6e6e6;
    font-size:12px;
    min-height:101%; 
   background-size: contain;
   -webkit-background-size:cover;
   background:url(https://images.cnblogs.com/cnblogs_com/taoXiang/1883703/o_2011181246481.jpg)  fixed;
   background-position:center 0;
   background-repeat:no-repeat;
}

#home {
margin: 0 auto;
opacity: 0.8;
width: 65%;
min-width: 1080px;
background-color: #fff;
padding: 20px;
margin-top: 40px;
margin-bottom: 40px;
box-shadow: 0 2px 6px rgba(100, 100, 100, 0.3);
}


#toTop{
  position: fixed; /*相对浏览器窗口定位*/
  bottom: 40px; /*距离浏览器窗口底部40px*/
  width: 150px;
  height: 174px;
  cursor: pointer;
  z-index: 998; /*层叠在较上层*/
  background-position: 0 0;
  text-align: center;
  background-image: url(https://images.cnblogs.com/cnblogs_com/taoXiang/1883703/o_201118041604toTop.png);
  background-repeat: no-repeat;
}