Hi Juliusz and list,

I started to clean up the CSS. Let me know if this PR makes sense as a 
first step: it groups all z-index values in one place, so they're not 
scattered all over galene.css:
https://github.com/jech/galene/pull/337

I also sent a second one for the sidebarnav. Its width was set in the 
.js file, so I moved it into galene.css so all numbers for adjusting the 
UI/UX experience is in one place:
https://github.com/jech/galene/pull/338

I tested both patched independently and then together, but test them 
also on your systems.

Any comments and constructive feedback is welcome.

Best regards,
Valent