As system fonts get nicer you might consider treating them like first-class citizens on your web site
Ire Aderinokun writes:
A few months ago, I wrote about how you can use system fonts in the browser using the built-in keywords that work with the font shorthand property (see Using System Fonts in the Browser).
Relatively recently, some websites and web applications have been adopting a new method for using system fonts in the browser. With this method, the fonts used by different systems are explicitly called themselves in the font-family property.
Read more from the source: bitsofcode