See what they say. PhoneGap, while a great idea seems to have issues like that. This is why we use Android Studio to create apps.
There may be other ideas over at Daniweb and Stack Overflow.
I've created a mobile app and styled it with CSS and ThemeRoller on Dreamweaver. It looks great on safari but when I use PhoneGap Build to test it on my Android device, the styling disappears.
I've tried embedding the CSS as well as the ThemeRoller style into my code without any luck.