How can I adjust text color and size on my Dawn theme image banner for different devices?

Okay, so my image banner looks great on my desktop. However, on my mobile, it is messed up.

Under the mobile layout section in the designer, I have the stack images on mobile and the show container on mobile checked. The heading text shows up as black on the mobile and white on my desktop. I want the text section to show up black on mobile and white on desktop too. How do I go about doing that? Also, how do I make the heading and text sections text smaller so it takes up less space.

My website is www.PennsylvaniaParks.org

Thanks so much in advance for any assistance you can provide.

@Justin34 - I think I gave you the code for this question in previous post you created