html {
    background: url('./image/bg-image.jpg');
    background-color: azure;
    background-size: cover;
    font-size: 12px;
}

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

.key {
    border: .4rem solid black;
    border-radius: .5rem;
    margin: 1rem;
    font-size: 1rem;
    padding: 1rem .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(1.1);
    border-color: #f63478;
    box-shadow: 0 0 1rem #f63478;
}

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

.sound {
    font-size: 1.2rem;
    text-transform: uppercase;
    letter-spacing: .1rem;
    color: #ffc600;
    font-weight: 800;
}