Standardize Stylesheets

[talon]

Though I am personally unlikely to contribute to the sites styles, I (and hold it as such that others) would be more inclined if we adopted a preprocessor and a style guide. I propose SCSS and css-bliss

[willklein]

I've personally enjoyed using cssnext via postcss. I'm not concerned what we use here though, I just like the idea of setting something up. 👍