We will be making improvements all round to the theme development experience.
There are still some remnants of Tailwind classes but I am making a concentrated effort to remove them in favour of more structured css. This should make overriding of things much easier.
Obviously, if you are intending to develop themes for Forum Spark in the meantime, please be aware that some things will be tricky to override or that some class names / structures may change.
We're also working on the ability to create themes that do not inherit from the base theme, as they currently do.
And finally, as alluded to in the APIs topic we're also working on a CLI tool assist in theme development workflows: