You can do the same in firefox fwiw, hit ctrl+shift C to open the inspector, then go to the style editor. It shows all loaded CSS files and the rules from within. I had a little trouble editing it however, for some reason copying and pasting something into it seemed to unlock being able to edit it by typing, not sure what's up with that. Oh, it seems to be modal, like vim, so copying and pasting must have accidentally ended up in edit mode. More normally, hitting 'i' gets the same effect.
But practically, I've not yet been able to find link colour or background colour here, so you win. I was trying to reproduce your effects using the tools at hand, but I lost.