Nav Drop-Down Spacing on 7.1

I'm trying to edit the spacing of the drop down items in my nav. I reached out to support and they said it's not an option but I could custom code it. Currently they are bunched together and it's hard to see the difference between which page you're clicking on. Would also be great to add a highlight option where the page you hover over highlights. See attached for screenshot of current dropdown. 

Super beginner with custom code over here!