Separate screens in different containers

We could separate each screen (the start screen, pomodoro screen, etc.) as a container. When the status changed, the current container should be hidden and the next one showed.

I propose the following containers/screens:
- Start container
- Pomodoro container
- Break container

It'd be cool if it had a transition (like the stack transition) when containers changed.

I have one doubt: should each container have different buttons and labels?