Ooh, that's a great question. I haven't thought about that (though I do generally try to make my designs responsive and mobile-friendly). I like your idea of a slow fade after scroll.
Things blinking/fading/shifting/changing when I'm taking completely unrelated actions (or, worse, all on their own) is one of the most unreadable/unusable design decisions I regularly face. It's a good way to get me to close a tab, regardless of any other factors.
