Ok, Codepen here.
One possibility is that you’re misunderstanding “100%” in terms of
height—it means “100% of the container’s height,” which is determined not by the window, but by how tall its content is. Without seeing your code, I don’t know, of course; but this is a very common tripping point. In many cases,
height:100% is a no-op.
Looking forward to your link.
(FYI, in your code sample above, your
<section> is unclosed. Dunno if that’s contributing to your problem, or if it’s just a typo in your post.)