#header {
	border:none;
	margin:0 auto;
	width:100%;
	height:100vh;
	background-image: url('https://juantrece.com/images/bannerjt.jpg');
	background-repeat: no-repeat;
	background-attachment: fixed;
	background-size: cover;
	background-position:center;
}

@media (min-width: 768px) {
	#header {
		border:none;
		width:100%;
		height:100vh;
		background-image: url('https://juantrece.com/images/bannerjt.jpg');
	} 
}