I just upgraded to J4, which went without a hitch.
So far as I can tell, the only issue that I'm having is cosmetic. On any article that has Tags, the tag styling has changed to a dark grey with dark colored text.
Where can I change this styling, and would this be a global change?
To be able to help you more effectively, could you please provide the URL of your website? This will allow me to review the specific styling issue you're facing with the tags.
Once I have this information, I should be able to guide you to the correct location to adjust the styling.