I think this is a bug where they didn't test large browser window sizes. At my laptop's maximum window height and my browser's default zoom level, the background doesn't get lighter than #BDDAE1 at the bottom before it transitions, but if I zoom out I can see it fade into unreadability.
Ahh, good call - my monitors are absurd. I tried it first on a 2048x1152... but I have that thing rotated sideways, so it's about twice the height of a typical 1080p monitor. Didn't fare much better on my normally rotated 2560x1440, but even then I nearly reach the bottom of the gradient before text colors change.
I guess I should just count myself lucky I haven't set up a rotated 4K monitor yet.
