body {
	display: flex;
	align-items: center;
	justify-content: center;
	min-height: 100vh;
	background-color: #e3f2fd;
	color: #fff;
}

.container {
	width: 780px;
	border-radius: 20px;
	padding: 35px 40px;
	background-color: black;
}

.container header {
	color: #b2b2b2;
	display: flex;
	align-items: center;
	justify-content: space-between;
}

header h2 {
	font-size: 1.6rem;
}

header .column {
	display: flex;
	align-items: center;
}

header .column span {
	font-weight: 500;
	margin-right: 15px;
	font-size: 1.19rem;
}

.volume-slider {
	accent-color: #fff;
}

.keys-check input {
	width: 60px;
	height: 30px;
	appearance: none;
	border-radius: 30px;
	background-color: #4b4b4b;
	cursor: pointer;
	position: relative;
}

.keys-check input::before {
	content: "";
	height: 20px;
	width: 20px;
	background-color: #8c8c8c;
	top: 50%;
	left: 0.3rem;
	border-radius: inherit;
	position: absolute;
	transform: translateY(-50%);
	transition: all 0.3s ease;
}

.keys-check input:checked::before {
	left: 2.1rem;
	background-color: #fff;
}

.piano-keys {
	display: flex;
	margin-top: 40px;
}

.piano-keys .key {
	cursor: pointer;
	user-select: none;
	list-style: none;
	color: #a2a2a2;
	position: relative;
	text-transform: uppercase;
}

.piano-keys .white {
	width: 70px;
	height: 230px;
	border: 1px solid black;
	border-radius: 8px;
	background: linear-gradient(#fff 96%, #eee 4%);
}

.piano-keys .black {
	width: 44px;
	height: 140px;
	z-index: 2;
	margin: 0 -22px 0 -22px;
	border: 1px solid black;
	border-radius: 0 0 5px 5px;
	background: linear-gradient(#333, #000);
}

.piano-keys span {
	position: absolute;
	bottom: 20px;
	width: 100%;
	text-align: center;
	font-size: 1.13rem;
}

.piano-keys .white.active {
	box-shadow: inset -5px 5px 20px rgba(0, 0, 0, 0.2);
	background: linear-gradient(to bottom #fff 0%, #eee 100%);
}

.piano-keys .black.active {
	box-shadow: inset -5px 5px 10px rgba(255, 255, 255, 0.1);
	background: linear-gradient(to bottom #fff, #eee);
}

.piano-keys .key.hide span {
	visibility: hidden;
}