CSS: 'cool' voting scheme, more mobile optimization

The WhoaVerse design has been updated to the 'Cool' color scheme, receiving the most votes on [this thread](http://whoaverse.com/v/ideasforwhoaverse/comments/28667). I also worked on making the mobile interface better. Here are the changes:

Dark:

* Add more contrast between visited and unvisited links
* Fix underlined text on button hover

Light:

* Add background color to comment forms
* Change sticky color to violet to fit with the new scheme

Both:

* Change voting color scheme to *Cool*, blue & violet:
    ![](http://i.imgur.com/asj66yj.png)
    ![](http://i.imgur.com/P1SD9pE.png)
* Improve mobile user interface with big expandos and larger flat list buttons:
    ![](http://i.imgur.com/NQ4Dron.png)
    ![](http://i.imgur.com/lzIiQFo.png)

I will make an announcement after the design is live... or, you can do it yourself if you want. All of the changes are in the list above (images would be removed, of course).