Thanks so much for your help. I think this is what I was looking for; it took me a while to discover that logic, but here's the code for anyone with the same case problem.
https://codepen.io/jeiemgi/pen/QWYpmGN?editors=0011
Two questions left.
I tried to make it so you never see the red background, ay ideas on that, so when the content ends it unpins the container.
How to make it snap faster with the function I have?
Anyways, I'll keep trying, but I appreciate your time. Thanks!