Should I use different backgroud colors in my app?

I want to design an app and my idea is to have 2 different background colors/themes:

  1. standard theme for sides where users just need to navigate
  2. theme for input sides where users need to make some input

The themes have different background colors, font colors and there is no top navigation on the second theme.

Is it a good idea? If not, please provide some usability rules.