iPhone 5 changes itself to a black theme with white and blue writing My iPhone 5 keeps changing itself to a black theme with white and blue fonts but then defaults back to white. I want the black them but have no idea where that is and how to turn on as the phone just does it itself. 

It's the whole OS. Not safari. I have have screen shots of my contact list, missed calls and a full contact.
This would be explained entirely by a change to your accessibility settings to "Invert Colors".

You can change that back in Settings->General->Accessibility.