I know Gruber likes to say that Markdown isn’t really designed as a replacement for WYSIWYG editors, but as someone who spent today fighting Pages, I cannot disagree more. Sure WYSIWYG is approachable, but do anything that needs to maintain a house style, and it all ends in tears.
In the end I asked an agent to recreate the PDF style in CSS, and vibe-code me something to render Markdown as a PDF via HTML. Probably took me longer than simply making the changes in Pages, but it preserved more of my sanity.