Changing Mobile App Header Color to that of Website Dynamically

Hi Alex T⚜️  I know you are busy at the moment, 

I am wondering if you can help me with a "color code" for the mobile app. I am wanting the header and footer colors to change with the Themes Day and Night Mode colors. 

https://github.com/unaio/una-mobile-app/blob/master/App.js

line 794&5 ->

header: {
backgroundColor: useTheme('colors.primary'),

I would like to use "Colors.header" in place of colors.primary, please can you let me know what code I should use.
backgroundColor: useTheme('colors.headercolor'),