I created a custom theme CSS for my application Flowblade and I’m quite happy with it.
The problem is that if system theme is set to Adwaita (or Paper or some others) the color defined for buttons does not appear in GUI, instead we get the Adwaita button colors.
Themes like Arc and Yaru do not have this effect when they are the system theme.
In the image below we have:
Top) custom theme with Arc as system theme, everything works
Middle) button color set to red in my custom CSS to confirm that we are setting the color correctly
Bottom) custom theme with Adwaita as system theme, now the button colors come from Adwaita and not from my custom CSS
My theory is that Adwaita sets some additional CSS properties that override my custom CSS or maybe my custom CSS does not fully override Adwaita, but I have no idea what these properties are. Or maybe it is something else completely.
Any ideas anyone?