Here’s a good ol’ fashion blog post by Rob Weychert where he looks into the new design system that he implemented on his personal website and specifically the typographic system that ties everything together:
According to the OED, a scale is “a graduated range of values forming a standard system for measuring or grading something.” A piece of music using a particular scale—a limited selection of notes with a shared mathematic relationship—can effect a certain emotional tenor. Want to write a sad song? Use a minor scale. Changed your mind? Switch to a major scale and suddenly that same song is in a much better mood.
Spatial relationships can likewise achieve a certain visual harmony using similar principles, and the constraints a scale provides take a lot of the arbitrary guesswork out of the process of arranging elements in space. Most of what I design that incorporates type has a typographic scale as its foundation, which informs the typeface choices and layout proportions. The process of creating that scale begins by asking what the type needs to do, and what role contrasting sizes will play in that.