Install fonts
I suspect the windows version of Safari is using an internal version of the Cocoa libraries for Windows, whcih is why it has Mac OS X font rendering (though I believe recent nightly builds at least have the option to use Windows' native font rendering for those who.
Eny builder for mac. Double-click the font in the Finder, then click Install Font in the font preview window that opens. After your Mac validates the font and opens the Font Book app, the font is installed and available for use.
You can use Font Book preferences to set the default install location, which determines whether the fonts you add are available to other user accounts on your Mac.
Fonts that appear dimmed in Font Book are either disabled ('Off'), or are additional fonts available for download from Apple. To download the font, select it and choose Edit > Download.
Disable fonts
You can disable any font that isn't required by your Mac. Select the font in Font Book, then choose Edit > Disable. The font remains installed, but no longer appears in the font menus of your apps. Fonts that are disabled show ”Off” next to the font name in Font Book.
Remove fonts
You can remove any font that isn't required by your Mac. Select the font in Font Book, then choose File > Remove. Font Book moves the font to the Trash.
Learn more
macOS supports TrueType (.ttf), Variable TrueType (.ttf), TrueType Collection (.ttc), OpenType (.otf), and OpenType Collection (.ttc) fonts. macOS Mojave adds support for OpenType-SVG fonts.
Legacy suitcase TrueType fonts and PostScript Type 1 LWFN fonts might work but aren't recommended.
If you are a designer and always switch between Mac and Windows, you will find that some of the beautiful fonts in Mac are not available in Windows. Even when you copy the font over, the Windows system does not recognize the font and can’t register it to the system. The reason is because those fonts are in dfont format which can only be used in Mac. To get it working in Windows (or Linux), you have to convert the dfont to TrueType format (ttf).
Download and install DfontSplitter.
Open the application. Click the “+” to add a dfont, or simply drag the dfont from the Finder.
For your info, the system fonts are located at the directory “System/Library/Fonts“. Alternatively, you can search for the font in the Font Book application and right-click the font and select “Reveal in Finder”.
Next, select the destination folder and click “Convert“.
You will now see a bunch of font files in your destination folder. Keep the one with the .ttf extension and delete the rest.
Now move those ttf fonts to Windows and double-click on it to install.
Note: DfontSplitter also comes with a Windows version. Alternatively, you can move the dfont to Windows and use DfontSplitter (Windows version)to convert the font to ttf format.