Offset/ outline of a stroke
Hi everyone!
I have a small problem but i really dont know how to fix it.
A few months back i created a standard stroke type, with an white outline/ offset around my stroke.
Now i need to get something similar, a small outline in black, but i cant figure it out anymore how i achieved this...
I searched everywhere, and my AI assistant also cant give my anything usefull. So i nearly tought it was impossible but i still have an object styles as proof for myself.

The same stroke, one with the offset the other one without.
Thanks already!
-Nick

