The other major alternative to consider is RTF. I standardised on that about 10y ago, planning for a 30y horizon. It is a more complex format than Markdown, still text-based, but biased towards WYSIWYG presentation and editing, while Markdown is usually not WYSIWYG in the editor. Both formats suffer from a lack of standardisation, though Markdown seems to have more problems in practice - I've never had an issue cause…
Interesting. Why not HTML? Browsers have native basic WYSIWYG editing built in, and almost every screen we look at is nowadays HTML, including the code editor. On a ` element, calling document.execCommand('bold') will make selected text bold in WYSIWYG mode. See https://jsfiddle.net/z0umpb3x/12/ for the concept. The main idea here is that I don't want to know any syntax like RTF, nor I want to use any tools.
Can you point me to a page in Firefox that I can use offline to WYSIWYG edit a hypertext document without needing to use the developer console to edit raw HTML?