WordPress/wp-content/themes/twentyfifteen/css/admin-custom-header.css

/*
Theme Name: Twenty Fifteen
Description: Used to style the header image displayed on the Appearance > Header screen.
*/

.appearance_page_custom-header #headimg {
	background: #fff no-repeat 50% 50%;
	background-size: cover;
	border: none;
	box-sizing: border-box;
	padding: 7.6923%;
}

#headimg h1,
#desc {
	color: #333;
	font-family: "Noto Sans", sans-serif;
}

#headimg h1 {
	font-size: 22px;
	line-height: 1.0909;
	margin: 0;
}

#headimg h1 a {
	text-decoration: none;
}

#desc {
	font-size: 12px;
	line-height: 1.5;
	margin-top: 0.5em;
	opacity: 0.7;
}

@media screen and (min-width: 772px) {
	#headimg h1 {
		font-size: 29px;
		line-height: 1.2069;
		margin: 0;
	}

	#desc {
		font-size: 14px;
	}
}

@media screen and (min-width: 783px) {
	#headimg h1 {
		font-size: 22px;
		line-height: 1.0909;
	}

	#desc {
		font-size: 12px;
		line-height: 1.5;
		margin-top: 0.5em;
	}
}

@media screen and (min-width: 1172px) {
	#headimg h1 {
		font-size: 29px;
		line-height: 1.2069;
	}

	#desc {
		font-size: 14px;
	}
}

@media screen and (min-width: 1313px) {
	#headimg h1 {
		font-size: 32px;
		line-height: 1.25;
	}

	#desc {
		font-size: 16px;
	}
}

@media screen and (min-width: 1383px) {
	.appearance_page_custom-header #headimg {
		background-position: 100% 50%;
		height: 1300px;
		max-width: 954px;
		padding: 83px 83px 0 0;
		width: 42%;
	}

	#headimg h1 {
		float: right;
		font-size: 27px;
		line-height: 1.1852;
		width: 248px;
	}

	#desc {
		clear: right;
		float: right;
		width: 248px;
	}
}