An alternative is to "opt-in" sort of how you can change the top bar color with enough Karma. Maybe that CSS is not loaded for people who dont have that same Karma? I assume people asking for the feature post often enough.

Edit:

To clarify what I mean is maybe toggling which style sheet HN gives you in settings would be ideal for all. Web standards are nice but they dont help in the minimalist ideals of HN too much.