Just a little suggestion; make the title bar stop expanding (on mobile) when you scroll back to the top. I've already seen the site logo and slogan the first time, after all.
About 2 weeks ago I had a lot of people on Reddit complain that it DIDN'T expand again, so I made the change to its current form. I'm glad to know there are differing opinions on this. :-)
Maybe I'll do both and take your advice for mobile and their advice for desktop.