How exactly did you go about doing that? For me I must use a word processor to edit the default stylesheet file—or to make my own Pandoc template in other words. In case you meant trying to do something in Scrivener, I did write a brief tutorial and creating your own document designs. It’s quite simple, and I would say even easier if you use LibreOffice, and ODT, as its stylesheet system is cascading, a bit like CSS is. I.e. to change the font to TNR you usually only have to change the master root style that everything else descends from. With Word, as I understand it, there is nothing like that and you have to change the font in each style that will be used.
But either way you’re just using word processor setup to do this, and then following the instructions provided to run your own Pandoc command-line in the compile settings—a good skill to learn anyway as Pandoc has a lot of really useful command-line flags.
Still, I guess I have no reason not to use Scrivener’s compile to Word with the two “Convert Markdown” and “Convert Multimarkdown” options selected…
This post here probably best describes the pros and cons of that approach. I can’t think of a single advantage to using Scrivener’s DOCX generator over Pandoc’s, especially once you learn the above. You’ll have way more design freedom since you’ll have everything Word or LibreOffice can do, rather than the small subset the compiler offers.