Develop a DESIGN.md

Use this prompt to take a project from "we have no visual identity" (or "our identity lives in someone's head") to a committed DESIGN.md that any coding agent can read and apply consistently. The process combines the grill-me skill (to extract brand decisions from the user) with the prototype skill (to make those decisions concrete and comparable before writing anything down).

What a DESIGN.md is

A DESIGN.md is a single markdown file describing a project's visual language in a form AI coding agents can act on. It sits between a Figma export (too specific) and a traditional brand book (too loose). The reference specification is google-labs-code/design.md: