Description of problem:

Some widgets in evolution are not readable by too dark background.
This come from gtk3 default theme's regression.

Version-Release number of selected component (if applicable):

F17, gtk3-3.4.3-2.fc17.i686

How reproducible:

always

Steps to Reproduce:

1. start evolution 
2. look an e-mail or browse calendar.
  
Actual results:

e-mail preview widget's background and calendar background(not working hours) are black(#000000) and this cannot readable.

Expected results:

e-mail preview widget's background and calendar background are gray and readable.

Additional info:

These widgets' background color is come from gtk default css's background.
Same trouble is found in arch linux and investigeted in gnome desktop bugzilla.

workaround without build: insert following lines to top of theme's gtk.css 
------------
* {
 background-color: @bg_color;
}
------------