Sticky Header Mobile Colors

Hi!

I was able to activate the sticky header for mobile devices but I am not able to set different colors than the ones already set on the main header.

I would like to do the same that can be seen on the computer (light color elements on a dark color background when sticky header is active). The main header is the opposite which is dark color elements on a light color background. On the screenshot, you can see elements are not visible.

Thank you for your help!

The page I need help with: [log in to see the link]