body {
    display: grid;
    place-content: center;
    min-height: 100vh;
    color: #fff;
    background-color: #e3f2fd;
    padding: 0 0.25rem;
}

.container {
    width: 100%;
    max-width: 780px;
    border-radius: 1.25rem;
    padding: 2rem 3.5rem;
    background-color: #000;
}

header {
    color: #b2b2b2;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 4rem;
}

header h2 {
    font-size: 1.5rem;
}

header .column {
    display: flex;
    align-items: center;
    gap: 0.875rem;
}

.column span {
    font-size: 1.125rem;
    font-weight: 500;
}

.volume-slider input {
    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: "";
    width: 20px;
    height: 20px;
    background-color: #8c8c8c;
    position: absolute;
    border-radius: 50%;
    top: 50%;
    transform: translateY(-50%);
    left: 0.25rem;
    transition: all 0.3s ease;
}

.keys-check input:checked::before {
    background-color: #fff;
    left: 2rem;
}

.piano-keys {
    display: flex;
    margin-top: 3rem;
}

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

.piano-keys .white {
    width: 70px;
    height: 230px;
    background: linear-gradient(#fff 96%, #eee 4%);
    border-radius: 0.5rem;
    border: 1px solid #000;
}

.piano-keys .black {
    width: 44px;
    height: 140px;
    z-index: 2;
    margin: 0 -22px 0 -22px;
    background: linear-gradient(#333, #000);
    border-radius: 0 0 0.325rem 0.325rem;
    border: 1px solid #000;
}

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

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

.piano-keys .black.active {
    background: linear-gradient(to bottom, #000, #434343);
    box-shadow: inset -5px 5px 10px rgba(255, 255, 255, 0.1);
}

.piano-keys .key.hide span {
    display: none;
}