I think this is probably about changing CSS, but I am not sure, is there a way to not have a blank line after a Heading?
/* spacing after headings in reading mode */
In live preview
--p-spacing controls how far new headings are spaced. The default value is 1 line which is fine. In source mode headings are not spaced before or after.
See also CSS Editor community plugin.
Got it, have the CEE Editor plugin up and going and the snippet working!