Hi
@kovidgoyal
Thank you very much for your interest and your input.
@DiapDealer
Following more extensive testing, I've found a resilient kind of stylesheet.

It's when the CSS is written in a
condensed form, not in a "beautified" form with a clean vertical layout. (more of it lowerdown).
So for now, your _v2 and _v3 scripts work only with EPUB which have this
beautified kind of stylesheet.
I reported yesterday night this finding to pingouinux who wrote a brand new version of his conversion tool. He tells me he tested it with python 2.7.3. and python 3.2.3.
I checked this new tool with both a condensed and a beautified stylesheet and it works for both.
I've enclosed a zip file containing:
-
pingouin, the new conversion tool for these two kinds of stylesheets
- style.css, a "condensed" kind of style-sheet
- newstyle.css, the processed with pingouin style.css
- styles1.css, a "beautified" kind of stylesheet
- newstyles1.css, the processed with pingouin styles1.css
I hope this makes some sense to you and I apologize if I have not been clear.
Maybe, integrating this new more efficient tool named "pingouin" and taking into account the comments of kovidgoyal above, there could be possible to build a version of the script with a broader field of use.