How do you achieve consistent UI design in vibe coded apps?

I'm building a database app - essentially a small CRM type program. For the UI, I'm implementing a ribbon style toolbar similar to MS Office apps. I'm having trouble keeping the design consistent across different areas of the app and Claude keeps overlooking simple errors like using different font sizes for the button labels or adding too much padding around certain buttons or dropdowns. How can I get clean, polished results in the UI without having to prompt claude on every little detail that needs to be f