PhoneGap/Cordova UI improvement .

We have an existing Cordova app running for Android and iOS platforms, and we would like to improve the screens look and feel. The candidate should be able to take a BitBucket ir Git branch of our project and run in in his/her machine to develop the changes to the existing screens reducing the JS files impact to the minimum. We already have graphic design mockups that could be used as reference. There are about between 15 to 20 screens, however most of them will be almost the same.