Importing custom css setting from .json file

I have been using a discontinued plugin to serve my custom css settings for my Genesis theme. Now I want to move my custom css from that plugin into the Genesus framework in my admin interface.

I’ve uploaded the .json file with the custom css to Genesis. But I have no idea where the .json file is, and how to insert it into my css so that the website display will be customized according to my css. ANyone give me any help on this?

The page I need help with: [log in to see the link]