body {
    margin: 0;
    background: #000;
    color: white;
    font-family: sans-serif;
}

#ui {
    position: fixed;
    padding: 10px;
    background: rgba(0,0,0,0.6);
    z-index: 10;
}

canvas {
    position: absolute;
    top: 0;
    left: 0;
}