Webdesign Frontend Advanced Skills?

TL;DR - Does anyone have skill markdowns or recommended settings to improve the UI output from Claude Code for frontend web design/css for an iOS app landing page?

Hey All - I'm working in VS Code in both Codex and Claude code to design a website for my app. I have a strong background for the general swift code design kit, copy, brand guidelines and adherence etc, but I'm now transferring those details into the website front-end for the first time.

Codex did a great job of starting the structure. I thought for sure that Claude was going to take the UI over the finish line, but it seems to be working backwards from V1 that Codex published. Anyways

The question is: How do I add more maturity to the designs that Claude Code or Codex are currently generating. I'm currently stuck in that classic loop of minor iterations that aren't progressing forward. The system I've developed for the app itself isn't quite translating yet. Are there starting points for skills or agent development that might provide a better starting point than drafting the design kit and markdown plan from scratch?