How to add some margin for icon space in Unity bar menu?

Question

How do you add a little margin for icon space next to menu items in Unity bar menu? I'm trying to make menu items appear more consistently aligned when there are both menu items with/without icon in the menu. I'm talking about this

I'm guessing this takes only few lines of changes in unity.css in /gtk-3.0/apps but I'm not sure what to change there. This is the default Ambience theme.

Answer 1

Not the clean solution you're looking for, but you could create an icon full of transparency.

It would accomplish the goal of consistent layout/indentation. Using transparency would also make it portable across themes.