Conform to styleguide better, dark UI expecially

Making some use of default classes for the manager view to play nice with most UI themes out there. It was barely usable on some dark UIs like _Ekini Like_ because of the custom colors in CSS.

And I've also took the opportunity to change console's `div` into `pre` to get a monospaced font for consistency.

Here's how it looks now in the dark:

![Screenshot](http://i.imgur.com/fS0Psyp.png)

...and seems fine in the light too:

![Screenshot](http://i.imgur.com/7VYlUMx.png)

You might want to look at the styleguide (`Ctrl+Shift+G` in Atom), it contains lots of themeable UI goodness.