* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
html {
    font-family: sans-serif;
    font-size: 16px;
}

body {
    background: url("../background.jpg");
    background-position: bottom center;
    background-repeat: no-repeat;
    width: 100%;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.keys {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
}
.key {
    user-select: none;

    width: 7rem;
    background-color: rgba(0, 0, 0, 0.4);
    border-radius: 0.5rem;
    border: 0.25rem solid black;
    padding: 1rem 0.5rem;
    margin: 0.8rem;

    font-size: 2.2rem;
    color: white;
    display: flex;
    flex-direction: column;
    align-items: center;
}
.sound {
    user-select: none;
    margin-top: 5px;
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.1rem;
    color: #ffc600;
}
.playing {
    transform: scale(1.1);
    border-color: #ffc600;
    box-shadow: 0 0 1rem #ffc600;
}