you would like to see HTML’s CSS converted to an editable RTF document stylesheet, and if you edit it in MS Word it will impact all relevant RTF content blocks. Right? Please correct if I am wrong

Yes! So when I define a paragraph style in the html document CSS, I will found the same paragraph style in the RTF document stylesheet.

I’m considering pd4ml for my software ( https://librogamecreator.wordpress.com/ ) and it would be very useful to have such a feature, so writers don’t have to go back to LGC, change CSS, export to RTF, all over again , whenever they need to change each paragraph to a certain style.