I am trying to insert a shadow on the top bar as you can observe in http://catalans.medialayer.net/
However when I introduce
box-shadow: 0 0 8px 1px #000;
the box just below (#zone-branding) overlaps that shadow. These would probably work if the regions in omega were in relative or absolute position.
I came out with the idea to insert an 'inset' shadow to #zone-branding in order to make it look like the top bar has a shadow.
However this solution introduces extra shadows.