You can ask Claude to create a "design language."

That's a lot more than just visual design, as it incorporates things like branding and interaction.

You can keep iterating it, until you have something that works. It can be a fair bit of work, but worth it. In my case, I uploaded final PNG screenshots, along with detailed README files, explaining each screen. I also uploaded MOV files.

I use ChatGPT, which has a "memory," so I just declare the current state as "baseline," and it will always riff off of the design language. Not sure if Claude can do that.

Also, with SwiftUI, you have hard limits on what you can do, visually. I tend to use UIKit for my release products, because of that. I find UIKit to be a pain, but with it, and Autolayout, I can do almost anything.