body {
	background: url('bg11.jpg') #999;
	background-size: auto 100vh;
	background-position:center top;
	background-repeat: no-repeat;
	background-attachment: fixed;
	z-index: 1000;
}
body::before {
	content: "";
	display: none;
	position: fixed;
	width: 100%;
	height: 100%;
	background:url('bg11mb.jpg') no-repeat left top;
	background-size: 100vw auto;
	top: 0;
	left: 0;
}
@media screen and (min-width: 1367px){

}

@media screen and (max-width: 1366px){
	body::before {
		display: block;
	}
}