body{background:#fff url(topbg.jpg) center 0 no-repeat;}
.arkTop{ background: url(logo.png) 0 20px no-repeat;}

/*响应式布局
----------------------------------------------*/
@media only screen and (max-width:800px) {
body{background:#fff;}
.arkTop{ background:#70a804;}
	
}

@media only screen and (min-width:300px) and (max-width:321px) {

}