Context: I'm a web professional with 20+ years in front-end, back-end, SEO, branding, content strategy and design. I've been using Claude (Opus 4.6 specifically) to build a complete website rebuild — design system, component library, page prototypes — without Figma. This is what I've learned about making it work well.
You don't need one magic prompt. You need a system — a set of documents that accumulate decisions over time, which Claude reads at the start of every session. The prompt that kicks off the design system is important, but the documents that constrain it afterwards are what make it actually work.