rem for components “root” and em for sub- parts of the components. Then, by adjusting the font-size of the root, we adjust all size-related CSS properties of a component at once. — @simurai
the y-intercept y = resulting font size Image credit: Jake Wilson, https://www.smashingmagazine.com/2017/05/fluid-responsive-typography-css-poly-fluid-sizing/ https://www.smashingmagazine.com/author/jake-wilson/