clean up and unify css files

[Igor Santos]

besides needing to unify the theme files, there are a lot of unused rules:

SymDiff, available for CSS preprocessors (Sass, LESS) and templating languages (HTML, Jade, Handlebars, JSX), reports any differences between the classes used in CSS and in your templates. Helium CSS scans a site and shows unused CSS, and so do UnCSS and Deadweight.