I wish if you could support the new CSS attribute tab-size ASAP.
Without it, check here what you may get (page-25):
http://richstyle.org/downloads/lpi-101-ar-ch-3.pdf

https://richstyle.org

We will add this to the development roadmap, but it is unlikely that we will be able to implement it for Prince 9.0, due to the number of other features we have to get through.