Great talk, learned lots of interresting things about CSS frameworks good & bad practice.
I Also liked that the talk was open for questions and discussion.
It was nice to learn more about the frontend side of things. This talk left the 'which framework is the best?' discussion aside to focus on how to create maintainable stylesheets. It's cool to see how frontend applies the open/closed principle. Especially the BEM methodology is quite interesting. Simple, yet genius. It's something that will be useful to have a better understanding of stylesheet and template structure.
And CSS reads from right to left. Who knew!