Hello,
I saw the screenshot you attached.
You can create an attribute and set promo as an item of the attribute and then you can assign the attribute to products and enable the option to display labels on product images.
Screenshot for Clarification: https://ibb.co/k9sYR83
Or if you want to use the translated one that you are using then try adding the following Custom CSS in the Global Custom CSS area under Theme Settings >> Custom CSS to change the color.
span.new.product-label {
background: orange;
}
Best Regards