Mark S is correct, the fonts are in Control Panel (font-family for view mode, code for code, editor for edit mode)
this from https://tiddlywiki.com/ font-family -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol" code "SFMono-Regular",Consolas,"Liberation Mono",Menlo,Courier,monospace editor (none listed) -- You received this message because you are subscribed to the Google Groups "TiddlyWiki" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/tiddlywiki. To view this discussion on the web visit https://groups.google.com/d/msgid/tiddlywiki/3aed6f0d-738e-4e2b-972f-6fb103d09c01%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.

