#banner {
    background: url("../images/background_banner.jpg") no-repeat;
    background-size: contain;
    background-color: #000;
    background-position-y: bottom;
}

@media only screen and (min-width: 767px) {
	#banner {
        background: url("../images/background_banner.jpg") no-repeat center center fixed;
        background-size: cover;
	}
}