I tested my use case (headings with hierarchical/outline/legal numbering) with GFM markdown, which took some custom css, but what I’m after does work, see attached html + css file (rename removing .txt).
Note that I attempted to contain the css with an <article> element just for this example; farmos implementation might need .region-content or a field specific class. I think this css approach is useful for both html and md fields.
pandoc gfm to html5 output.html.txt (7.2 KB)
If you’re discussing such a document, it’s really handy to say, “Let’s talk about item 3.1.2.”
Also note the discussion of preventing use if h1 in user editable fields, per w3c. This should apply to both html and md fields.
I didn’t look into the strikethrough problem, but strikethrough is very handy to indicate recently removed items in a how-to, so people know that you intentionally removed something, and they should not cruise through the usual steps on auto-pilot. 