The following is a guest post by Tom Genoni. Tom is going to introduce us to the thinking and process behind Optimizely’s new UI library / Sass framework. Part 2, tomorrow, will be by Daniel O’Conner who will look at some of the technical and integration bits.

When I first started working on web projects, stylesheets were seen as a necessary evil. It was neither a real language to be taken seriously by a computer-science minded engineer nor simple enough for a designer to fully own and understand. With few best practices, organization of the CSS was always ad hoc