Confirmed.
The method seems to be
- Notes containing markdown $Text are assigned the “Markdown” prototype – either the built-in prototype or a prototype of one’s own invention
- The “Markdown” prototype contains the $HTMLPreviewCommand, which can be the built-in preview command (from the Tinderbox.app package) or any other you choose
- The “Markdown” prototype is assigned a “Markdown template”
- The “Markdown template” contains the desired styling – the built-in HTML template can be modified to add CSS, if desired.
- The $HTMLPreviewCommand generates HTML
- The “Markdown template” assigns styles for the generated HTML