It does... and at first it can get to be confusing. After you play with it a bit then you will start to grasp it. It took me a while - but look at me now, I can even give help to others at times!
Suggestion... make a child style of your current style and then go to town playing with it (tweaking here and there to see what changes). Do NOT make it a style that users can choose (you will still be able to since you are an Admin). If you have a developer board set up then you can just do it on that - but when I first started I hadn't set up a separate restricted site (I have one now on my server here at the house that I duplicate all my forums on but I still find that I do my tweaking on a child style of my live site).