They declare an unnecessary amount of different font-sizes that upon inspection, don’t come close to resembling a sane type scale.
There are several pre-defined classes for setting the typeface of a page or element. It is suggested that you customize or extend this module to suit your own needs. As tachyons is a toolkit for designing performant webpages it comes with a variety of font stacks that utilize attractive system fonts with appropriate fallbacks.
All we have to decide is what to do with the time that is given us.
Relying on systems fonts greatly improves page performance and can also help your web application/site blend in with the user's operating system. Readability is strongly linked to familiarity, so this helps create a more fluid reading experience, allowing your users to focus on your content.