body {
    background: #222;
    color: #fff;
    font-family: Arial, sans-serif;
    text-align: center;
    margin: 0;
    padding: 0;
}

h2 {
    margin-top: 20px;
}

#pong {
    background: #111;
    display: block;
    margin: 20px auto;
    border: 3px solid #fff;
    border-radius: 8px;
}