ttf file containing a single font weight (regular). ttf files for each font weight (bold, light, regular, etc.) On High Sierra, however, there is only one. Previously, the macOS font files in the /System/Library/Fonts folder included separate. I am looking to replace the system font on my Mac from SF Regular to SF Compact. Apple's new system font, 'San Francisco', has two versions - 'Compact', for display on small screens like the Apple Watch, and a regular version for display on larger screens like macOS devices.