App redesign - initial designs

In my first designs for the app I made an overall style and applied these to all of the screens, leaving out some of the detail that would be needed later as these are still initial stages. Here, I just wanted to get an overall style down for the app and then I can add in details later.

As decided in the type explorations, I used Source Sans pro as my typeface. This seemed to work well as it suited larger pieces of text such as ones that would be in the quiz. I made the buttons semi bold so that the user could differentiate from the buttons used in the quiz for the answers. I also made all the buttons rectangled with rounded edges to give the appearance of the app more softness, as seen from research this seemed to work well. In the first 2 screens I played around with having the home button being the only icon in the bar at the bottom of the page - I will need to refine this icon more and apply it to the rest of the screens once I have done this. I will also need to add in a back button to the app, I think this will be placed alongside the home icon so that there is not too much extra space at the top and bottom of the screen.

The buttons also have a shadow behind them to appear as if they are floating or raised from the screen, as actual buttons would be. This makes them appear less flat. The main issue I am struggling with is the colours of the screen. The grey colour scheme seems very dull and doesn't really draw in the user to use the quiz. However, by adding any other colours in this may confuse the user. The only way I can think of around this is to use a very dull, dark blue, as this is very different to any of the colours included in the political palette. Also, the gradient background doesn't give the effect I wanted behind all of the elements in the app. I need to find another way to indicate the users party, and still include the colours, and make the app appear more interesting.