body {   
                 background-position-y: top;
                 background-image:url("https://images.cnblogs.com/cnblogs_com/mummyblog/1546580/o_background.png");
                 background-repeat:repeat-x;
                 background-color:white;

}
#navigator{
background-color:#000000;
background-color:rgba(0,0,0,0.2);
}