For consistency, I would remove the line between Basemaps and Overlays and increase the gap minimally to the same size gaps you are using between Places of Worship and municipal Buildings.
Sort of, the line is gone, that is good. Now you need to have a gap between the groups for Basemaps and Overlay. Same distance as between Places of Worship and municipal Buildings.
For consistency, I would remove the line between Basemaps and Overlays and increase the gap minimally to the same size gaps you are using between Places of Worship and municipal Buildings.