font-family: -apple-system, sans-serif;
There are other names to access the system font on older macOS versions (when it was OS X). See, for example, GitHub’s CSS for a full stack of system fonts. For my use case — local Markdown preview and export —
-apple-system is enough.
The San Francisco font family is complete, having italics, all weights, small-caps, and a wide Unicode range.
".SF Compact Rounded"
".SF Compact Text"
".SF UI Display Condensed"
".SF UI Text Condensed"
I couldn’t reference
".SF UI …" in CSS. “SF Mono” is bundled in the
Terminal.app package. Some of the fonts are available for download at the Apple Developer site.