body {
    background: url(https://www.cnblogs.com/images/cnblogs_com/hongou/1421968/o_timg.jpg) fixed;
    background-size:100%;
    background-repeat:no-repeat;
}
#home{
    background-color: #ffffff;
}
#home{
filter:alpha(opacity=80);  
      -moz-opacity:0.8;  
      -khtml-opacity: 0.8;  
      opacity: 0.8;  
}