How to reduce the HEIGHT of <br>/<br /> ? With: CSS

My Gigko Tree:

As of right now I'm using a clunky way of using "Line breaks". They are great. But. The "Height" of them, is too much.

I don’t how I would change.
<br> height
that, using CSS.

I recommend create a Copy of the Tree, to see how it looks like within Edit Mode.