Nirvana css for plug-in

Hi!
I’m using Nirvan as a theme (through a child-theme). I would like some of my plug-ins to use the same css as I have in Nirvana but don’t know how to address them since the settings is set in “Nirvana settings”.

Where do I find the outcome of the Nirvana settings, or the address/name to where the plug-in should get the css?

Thanks!