The debate surrounding functional CSS has some ready to dive in and others adamant that it introduces new and undesirable patterns into our code bases. In this talk we’ll take a deep dive into the world of functional CSS and compare it to other OOCSS methodologies. We’ll explore the history of functional CSS and where it came from, and debunk or support the various critiques of this approach. We’ll refactor an application from a more classic CSS model to one that leverages the library tachyons.io and do some rapid prototyping in the browser with it.