Targeting header styles for default pages

Site URL: https://gardenia-bobcat-xhwl.squarespace.com

Right now, I have the Dynamic header set up for most of the pages of the site...

The problem with this is that for the default pages — product pages, shopping cart, 404, etc — that use the Lightest 1 setting of the theme, so the background color is white, the header is also white. 

I'd like to have the header for those pages be the solid maroon of the palette —hsl(338, 63%, 30%). Is there custom code I can add to make that happen?

Thank you!

In the short term, to keep the site usable, I added a maroon background to the logo, so it's visible on the pages with the white header. Not ideal, but I had to do something to get the site live.

Any help I can get would be really appreciated. 

Do you still need help on this?

I do, yes. I really dislike the maroon background I put into the logo artwork, but had to get it live bc a direct mail piece went out to drive traffic.