body {
   margin:0; padding:0;
   background: url(//https://images.cnblogs.com/cnblogs_com/lhsghhqgmzy/1440921/o_74e0339b3a4084c25eee10d11671535c.jpg)no-repeat fixed;

    color: #000;
     background-repeat: no-repeat; 
     background-attachment: fixed; 
     background-position: center 0; 
     background-size: cover; 
     background-color: #e6e6e6;}
#home {
margin: 0 auto;
opacity: 0.72;
width: 75%;
min-width: 1080px;
background-color: #fff;
padding: 30px;
margin-top: 50px;
margin-bottom: 50px;
box-shadow: 0 2px 6px rgba(100, 100, 100, 0.3);
}
#con{ 

    position:absolute;
    top:0;
    left:0;
    height:100%;
    width:100%;
    background-image:url("maskimg/star.jpg"); 
    background-position: center 0;
    background-repeat: no-repeat;
    background-attachment:fixed;
    background-size: cover;
    -webkit-background-size: cover;/* 兼容Webkit内核浏览器如Chrome和Safari */
    -o-background-size: cover;/* 兼容Opera */
    zoom: 1;    
}