You can use it with css-in-js libs like styled-components as well. It exports two helper functions, "rhythm" and "scale".

"rhythm" is a virtual unit that's the distance of one line-height. All spacing within Typography.js are based on it. Using "rhythms" for other spacings on your site ensures everything stays consistent as you make styling tweaks.

"scale" is a function to pick font sizes off the scale you setup (with scaleRatio). This let's you tweak the body font size and all other font sizes will move along with that.