body{
background-image:url("https://images.cnblogs.com/cnblogs_com/windyz99/1746695/o_200421064145DJI_0339-%E7%BC%96%E8%BE%91.jpg");
background-repeat:no-repeat;
}

#leftcontent,#header,#centercontent,#mytopmenu,.footer{
opacity:0.8;
}