Fourth thing in a row they've announced that I wanted to try and couldn't.

Previous comment with the prior 3: https://news.ycombinator.com/item?id=47794419

It's rolling out progressively, it works for me – it actually seems very polished, the examples are really good; and it lets you create your design system from your codebase

It's rolling out progressively throughout the day.

It’s working now, try it again.

Perfect, that's CC design for you :-)