Allow global configuration of the font family of all visually rendered text content.
As part of satisfying provision one of this checkpoint, provide a configuration option to override font families specified by the author or by user agent defaults.
As part of satisfying provision one of this checkpoint, offer a range of font families to the user that includes at least:
the range offered by the conventional utility available in the operating environment that allows users to choose the font family, or
if no such utility is available, the range of font families supported by the conventional APIs of the operating environment for drawing text.
Sufficient techniques
For text that cannot be rendered properly using the user's preferred font family, the user agent should substitute an alternative font family.