html, body { -webkit-backface-visibility:hidden;}

#first {
  background-color: #000;
  width: 100%; max-width: 1920px;
   height: 100%; max-height: 1080px;
   background: url('images/bg.png') no-repeat center; 
   background-size:cover;
   position:relative;
}

.bgwidth { width: 100%; max-width: 1920px; }
.bgheight { height: 100%; max-height: 1080px; }

@media all and (orientation:portrait) { 
	background-image:url('images/Mobile_Art.jpg');
	background-repeat:no-repeat;
	background-position:center;

}