There is almost nothing you can do in CSS that has security implications. Not zero, but the footprint is small enough that I blindly trust the robots.

I pay attention to frontend code just to keep code quality up. Frontend work is relatively low stakes from a security perspective and I've never seen the robots do anything problematic. I don't vibe code React but I think you could get away with it today.

Backend is a totally different story.

That's still a lot of engineering getting displaced.