Everything you put in the obsidian.css will modify the default theme. So I don’t have access to the orignal css. I can view it to work out what’s going on using the techniques described in the Getting comfortable with Obsidian CSS post.
So if you put the code I posted above in a blank obsidian.css you will get what you see in my screenshots (bar a few extra css mods have that you can find on here).
Hope that helps.