font-family: -apple-system, BlinkMacSystemFont,
    "Segoe UI", "Roboto", "Oxygen",
    "Ubuntu", "Cantarell", "Fira Sans",
    "Droid Sans", "Helvetica Neue", sans-serif;
Font OS
-apple-system OS X (10.11+), iOS (9+)
BlinkMacSystemFont OS X, Chrome
Segoe UI Windows
Roboto Android 4.0+
Oxygen Linux, KDE
Ubuntu Linux, Ubuntu
Cantarell Linux, Gnome
Fira Sans Firefox OS
Droid Sans Android (until 3.2)
Helvetica Neue OS X (10.9)

Reference: https://medium.com/design/system-shock-6b1dc6d6596f