Blue iOS app text

The navigational text at the top of most apps (cancel, back, close, next, etc) is blue and difficult to see. How can I change it? When I look at the same apps on my wife's phone the text is usually white (which provides MUCH better contrast against a dark green or dark blue background). I've noticed this on both my old iPhone 6s and my new iPhone X. Both are using iOS 11.2 (15C114). I have both larger text and bold text enabled under Settings->General->Accessibility. I tried switching them both back to default but it has not fixed the issue. What am I missing?