Normal input fields & formula fields etc have a fixed font/style for the title and thus it's heading attributes cannot be changed in terms of font/colour

You can of course change formula field contents in terms style of font/colour/size

which also includes layout headings.

I'm guess that Nixox fix the font so that it is uniform across the Iphone/Ipad/Mac etc.

this also applies to the grid spacing

Personally I think Ninox looks terrible on the iphone