.header-ad {
	text-align: center;
}

.header-ad img {
	width: 728px;
	max-width: 100%;
	height: auto;
	display: inline-block;
}

.header-ad img.retina {
	display: none;
}

@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
	.header-ad img.non-retina {
		display: none;
	}

	.header-ad img.retina {
		display: inline-block;
	}
}

@media only screen and (max-width: 600px) {
	.header-ad {
		display: none;
	}
}