3D FlipBook - How to add a JS/CSS particle background to Lightbox background

Hi,

I would like to add this: https://codepen.io/bob6664569/pen/rOzmve as a background, but Im not able to do it. I can add it to the main page where the flipbook is contained, but not the to Lightbox flip book background. Where do I need to add the HTML/CSS/JS code to have a flip book with that "particles" background?

Thanks!