#main-bg {
	/* Location of the image */
	background-image: url('/assets/img-temp/1920x1080/img1.jpg');
	/* Background image is centered vertically and horizontally at all times */
	background-position: center center;
	/* Background image doesn't tile */
	background-repeat: no-repeat;
	/* Background image is fixed in the viewport so that it doesn't move when 
     the content's height is greater than the image's height */
	background-attachment: fixed;
	/* This is what makes the background image rescale based
     on the container's size */
	background-size: cover;
	/* Set a background color that will be displayed
     while the background image is loading */
	background-size: contain;
}

@media only screen and (min-width: 400px) {
	#main-bg {
		background-image: url('../assets/img-temp/1920x1080/img2.jpg');
	}
}