Counter-argument: the cascade in CSS was a massive design mistake and it shows even more in this particular case.
With LLM-assisted development you spend more time reading and reviewing the generated code. The cascade in styles is nowhere near as readily apparent as something like Tailwind.
If you're arguing down that route, LLMs can bulk-apply style attributes exactly where they're needed. Every element precisely described, no need for CSS and style-sheets at all.
I haven't seen cascades be a problem since the days of monolithic, app-wide stylesheets, and no project I personally know of works that way anymore.
Just about everyone uses component-specific styles with a limited set of selectors where there are very few collisions per property, and pretty clear specificity winners when there are.
If the alternative to the cascade is that you have to repeat granular style choices on every single element, I'll take the cascade every time.