body {
    background-color: black;
}

.center {
    display: flex;
    justify-content: center;
}

.key {
    display: inline-block;
    width: 2rem;
    height: 5rem;
    margin-right: 2px;
    background-color: white;
}

.key:hover {
    background-color: gray;
    cursor: pointer;
}

#piano {
    background-color: midnightblue;
    padding: 5px;
    text-align: center;
}

#randomKey { background: linear-gradient(to bottom right, mediumvioletred, orange); }
#randomKey:hover { background: linear-gradient(to bottom right, purple, orangered); }

#title {
    color: white;
    font-weight: bold;
    font-size: x-large;
}