DESIGN.md: How to Apply Apple's Design System with a Single File

Google published DESIGN.md, a Markdown spec that lets AI coding agents read brand design systems from a project root file and apply them in UI work.

The article explains three ways to use it: generate, import, or write DESIGN.md directly, plus the tools that support this workflow.

It highlights how this can reduce repeated prompt instructions and help AI tools keep product UI consistent with brand style.

It also includes Jordan Lord's three filters for deciding whether to build a product before starting development.