Genesis Sample Child theme - responsive header image and header area

style.css

/*in this section of code */ 
@media only screen and (max-width: 600px) {

/* I added this code block */
#header {
	    background-size: contain !important;
		min-height: 100%; 
 		overflow-y:hidden; 		
	} 

/* I modified the code block below to show height as 100% instead of 100px */

/* Image Header - Partial Width
------------------------------------------------------------ */

.header-image #title-area,
.header-image #title,
.header-image #title a {
	display: block;
	float: left;
	height: 100%;
	overflow: hidden;
	padding: 0;
	text-indent: -9999px;
	width: 400px;
}