Rise

<style>
.css-container {
    width: 100%;
    overflow: hidden;
    padding-bottom: 64px;
    background-color: #0E1525;
}
@media screen and (min-width: 480px) {
    .css-container {
        position: sticky;
        top: 64px;
        height: calc(100vh + 64px);
        transform: translateY(-64px);
    }
}
.css-canvas {
    position: absolute;
}
</style>

<div class="css-container">
    <canvas class="css-canvas"></canvas>
</div>

<script>
let gl = {
    width: 480,
    height: 240,
    scrollY: 0,
    speed: 3, // min 3 max 100
    alpha: 1, // max 1 min 0
    rgb: ['87,171,255', '242,224,136', '255,189,122', '122,235,141', '166,148,255', '245,249,252'],
    rid: 0,
    init() {
        gl.width = window.innerWidth;
        gl.height = window.innerHeight;
        gl.scrollY = window.scrollY;
    }
};

gl.canvas = document.querySelector('canvas');
gl.ctx = gl.canvas.getContext('2d');
gl.main = main;
gl.init();
gl.main();

window.addEventListener('resize', function() {
    gl.init();
    gl.main();
});
window.addEventListener('scroll', function() {
    gl.init();

    // scroll value: gl.scrollY
    // scroll range for speed effect: min = 0, max = 1.75 * gl.height
    // scroll range for alpha effect: min = 1.25 * gl.height, max = 2 * gl.height

    // speed value: gl.speed
    // speed range for scroll: min = 3, max = 100

    // alpha value: gl.alpha
    // alpha range for scroll: max = 1, min = 0

    // scroll direction?
    // scroll down: gl.speed += n, gl.alpha -= n
    // scroll up:   gl.speed -= n, gl.alpha += n

    // n?
    // scroll delta per time unit

    // ...
});

function main() {

    function rndw() {
        return Math.random() * width - width / 2;
    }
    function rndh() {
        return Math.random() * height - height / 2;
    }
    function ball() {
        let rw = rndw(), rh = rndh(), w1 = Math.random() * width, w0 = w1, i = gl.rgb.length - 1;
        let c = Math.random() < 0.75 ? gl.rgb[i]: gl.rgb[Math.floor(Math.random() * i)];

        return {
            update() {
                w1 -= (gl.width > 480) ? gl.speed * (gl.width / 1440) : 3;
                if (w1 < 1) rw = rndw(), rh = rndh(), w1 = width, w0 = w1;
            },
            render() {
                ctx.lineWidth = 24 * (1 - w1 / width);
                ctx.lineCap = 'round';
                ctx.strokeStyle = 'rgba(' + c + ',' + Math.min(gl.alpha, 1 - w1 / width) + ')';
                ctx.beginPath();
                ctx.moveTo(width * rw / w0, height * rh / w0);
                ctx.lineTo(width * rw / w1, height * rh / w1);
                ctx.stroke();
                w0 = w1;
            }
        };
    }
    function loop() {
        ctx.setTransform(1, 0, 0, 1, 0, 0);
        ctx.clearRect(0, 0, width, height);
        ctx.translate(width / 2, height / 2);

        for (let b of balls) {
            b.update();
            b.render();
        }
        gl.rid = window.requestAnimationFrame(loop)
    }

    gl.rid = window.cancelAnimationFrame(gl.rid);

    let { width, height, canvas, ctx } = gl;

    let dpr = window.devicePixelRatio;
    if (dpr > 1) {
        canvas.style.width = width + 'px';
        canvas.style.height = height + 'px';
        canvas.width = width *= dpr;
        canvas.height = height *= dpr;
        ctx.scale(dpr, dpr);
    } else {
        canvas.width = width;
        canvas.height = height;
    }

    let balls = [];
    for (let i = 0; i < 800; i++) balls.push(ball());

    loop();
}
</script>