LLM are actually really bad at writing CSS. CSS is 20% logic and 80% art. The machines just don't understand what is attractive and what is ugly. I hand write all of my CSS and I don't see that changing any time soon.

I had this opinion recently until I started using the Figma MCP with Claude to import my live app into Figma Make, get it to edit things where it actually understands layout and margins and what looks good, and then pull it back into the app with MCP. I was shocked at how good it works. Sure, Claude sucks at CSS, but Figma nails it even for the worst designed pages.