Thanks a lot Jack.
I actually tried this, that I wrapped everything into container (which has position fixed while animation is running), but this wasn't suitable for me, because I'm trying to run GSAP animation on child element. The child element is child of parent element. Parent element has siblings which I'd like to be visible (without any movement = this means no whitespace creation) while doing the animation (the parent element is < 100vh => siblings are visible). The only suitable solution I can come up with is to wrap parent element and it's siblings into container, but since the parent element and it's siblings are children of document.body, that means I should pin document.body? This doesn't seems right to me. Or would that work all right?
Thanks.