#main {opacity:0.7;overflow: hidden;};
#header {opacity:0.8;};
#centerbody {
 background-image: url(https://images.cnblogs.com/cnblogs_com/brownChan/1249239/o_a792353….jpg);
 background-repeat: no-repeat;
 background-clip: content-box;
 background-size: 100% 100%;
}