Explore updates to our fluid type calculations for simplicity and accessibility

## Overview

We last refactored our fluid type calculations in 2021 (#1560), but since then there's been more research and development on the topic.

Our current calculations seem to be working well, but [there may be an accessibility issue with the negative number in the calculations](https://front-end.social/@aardrian@toot.cafe/109824015693243455).

Some more recent calculators do not seem to rely on negative calculations:

- [Utopia: Fluid type scale calculator](https://utopia.fyi/type/calculator/)
- [Min-Max Value Interpolation](https://min-max-calculator.9elements.com/)

We may want to test our fluid type more thoroughly, and possibly revisit our mixin to see if we can generate something even nicer.