[docbook-apps] [Website] Refining some style issues (CSS ?)

Hi again,

sorry, mea culpa, sometimes one types before checking the obvious.
I solved the first point: different width. It was due to a lacking
dependency in my Makefile so that one file was not remade after
changing the customization.

But the two other "problems" remain - how to obtain a continous
appearance of the left side of the screen in one color.

Cheers,
  Marc