I am not sure the good strategy is to try to exactly reproduce in the mobi what our book looks like in MS-Word or Atlantis. I personnally do not work that way.
I have a master CSS file that I always use because I know it works well and is KDP compliant, so the first thing I have to do is to replace the styles.css by mine and clean the code generated by Atlantis, for instance:
<h3 class="h31" id="ncx3">Internal</h3>
becomes:
<h3 id="ncx3">Internal</h3>
And I´ll do the same for <h2> to <h9>, <ul>, <ol>, <li>
It is a little bit more complicated for <p> where I'll have different classes ... and Atlantis do not use the same style name that MS-Word. (See
your answer to Chang).
I have an idea to workaround this I have to check.
In conclusion, and taking into account my
last post, the flow that I foresee should work for me is:
MS-Word > .docx > Atlantis > .epub > Script1 > .epub > Sigil > .epub > Script2 w/ Kindlegen > .mobi
And if I do the right things right in my script (in case of urticaria):
MS-Word > .docx > Atlantis > .epub > Script w/ Kindlegen > .mobi