Change look of "Sold Out" stamp on Publisher theme

Hi, I’m wondering how I can change the look of the “Sold out stamp” that shows up when you’re viewing a sold out item inside a collection?
This is probably done via some custom CSS, right? I just don’t know where to start.

Could anyone help me out please?

Hi @Lizzy124

You can do this here:
Theme Settings > Badges > Sold out badge color scheme
Note: If you plan on changing colors, create a new Color Scheme or other Sections using said scheme will also be updated.
Theme Settings > Colors > Add Scheme

Regards