Just for cross-reference: https://github.com/NodeBB/NodeBB/issues/2060
I think I agree with the idea and that it would be useful although I don't see ourselves prioritizing this feature for the next major version at least.
@julian, I think I fixed this issue. I rolled back to a snapshot before I installed NodeBB and re-cloned the 0.5.1 branch and it installed without an issue and I have sweet, glorious CSS!