CSS editing

How can you edit information in CSS on the activello theme for Wordpress and Woocommerce? I have a plugin which is not working properly and needs to have it’s CSS entry amended in order to have it working correctly.
We were using a different theme which could be amended via a premium theme but this is something we were trying to avoid if possible.

Hey there

Thank you for the question
Can you tell me what is your goal? a little bit more about the question?
Editing css files of the theme is not recommended but you can add new rules, new rules of css can be added in the appearance > customize > additional css