html {
	font-size: 15px;
	background: url(https://i.imgur.com/VcVRrx5.jpg) bottom center;
	background-size: cover;
}
body,html {
	margin: 0;
	padding: 0;
	font-family: sans-serif;
}

.keys {
	display: flex;
	flex: 1;
	min-height: 100vh;
	align-items: center;
	justify-content: center;
}

.key {
	border: .4rem solid black;
	border-radius: .5rem;
	margin: 1rem;
	font-size: 1.5rem;
	transition: all .07s ease;
	width: 10rem;
	text-align: center;
	color: white;
	background: rgba(0,0,0,0.4);
	text-shadow: 0 0 .5rem black;
}

.playing {
	transform: scale(1.2);
	border-color: #ffc600;
	box-shadow: 0 0 1rem #ffc600
}

kbd {
	display: block;
	font-size: 4rem;
}

.sound {
	font-size: 1.2rem;
	text-transform: uppercase;
	letter-spacing: .1rem;
	color: #ffc600
}