Styling on Android 4.x


Hello, community!
I’m using NativeScript for a couple of months already and it was pure fun, but finally I’ve encountered a trouble I could not solve by googling!
I was always testing my apps on Android 5.x, but now i’ve got to check them on 4.x as well and i do see a strange styling issue. The colors that look fine on 5.x, look pretty dull on 4.x
Uploaded 2 images:, the 1st one is 5.x, the second one is 4.4. My styling is straightforward: i just set the color for the buttons. I’ve tried added button to ‘btn’ and similar classes and it did not help.
Maybe you’ve got any hints?
Thank you!