Typography is one of those things that looks simple from the outside and turns out to be a discipline with decades of accumulated theory. Type scales, modular scales, vertical rhythm — there are whole books.
The golden ratio type scale is based on a simple idea: each step in the type scale is φ times the previous one. Start at 1rem (16px), multiply by 1.618, and you get a scale that always feels harmonious.
This toolkit packages that idea as a set of CSS custom properties. Drop it into any project and you get a complete type scale, line-heights based on the golden ratio, and a spacing system built on the Fibonacci sequence.