If you're a stickler for details, have we got a treat for you: the latest update to Google Keep Notes (née Google Keep) colors the navigation bar to match the note you're currently viewing.
While it isn't quite as big a deal as, say, a full redesign, the effect is pleasing: your entire screen, from top to bottom, is now a uniform color when reading or editing a note. The nav bar does change to black while the keyboard is on screen, though.
Is this a minor tweak? You bet your bottom dollar, but it's small touches like these that make an app feel polished. The update should be live on the Play Store now, but you can also grab it from APK Mirror.