Add printer styl-styles
Remove inline css
Remove unnecessary elements and add some css-classes
Rename application.css.styl to .css.erb.styl and add _images.styl so we can use images from our styles as said in here: https://github.com/lucasmazza/ruby-stylus/issues/12#issuecomment-2638777
Add main-navigation.styl where are all styles related to main-area navigation
Add styles from .css-files to .styl-files and rename some css-classes