[MrVandemar]

Can't argue with the success of Markdown.

It's still a lousy "spec", and, again, I often see people wishing for a Markdown web browser, but I don't see anyone implementing such a thing. You'd think it would be an instant success!

Yeah, I am a jaded techie. I wanted to like Markdown and used it extensively for a little while and wound up utterly loathing it for anything other than jotting down a quick, ephemeral note.

But, back to my original response: if you want a usable alternative to HTML, right now, a simple XML grammar + style sheet will deliver that. Firefox, Chrome, Edge and Safari will render it nicely. Heck, even Docbook would work (which is overkill, but has vast and mature tooling available).