body {
    background: linear-gradient(125deg, red, green, blue);
    width: 100vw;
    height: 100vh;
    overflow: hidden;
    margin: 0;
}

#canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

#collisionCanvas {
    opacity: 0;
}