docbook: change css style
docbook: change css style

A handful of random personal preference:

- Force sans-serif for the text.
- Quote code sample literal inside a single-quote pair.
- Show emphasis in blue-green italics.
- Do not use itarlics for term definition, but show them in navy.

Signed-off-by: Felipe Contreras <de77a8b9cd239b204c19c52ed62e48ab47243362@gmail.com>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git