Tabs project with fixed background

I’m using a tabs template for an Ionic project and have set the a background image. However, when the transition throw states occurs, the background is also affected by the animation. I want that the background always stay fixed on entire application ( on transition throw states and sub-states).

This project exemplifies the problem:

I also tried to assign the background property to the body but it doesn’t work.

So, does anybody know how to always keep the background image fixed and only animate the content ?