A comprehensive reference for Apple platform design decisions covering HIG compliance, Liquid Glass materials, SF Symbols, typography, and app architecture patterns. You'll reach for this when choosing semantic colors, implementing Liquid Glass effects (not just blur), picking SF Symbols rendering modes, or structuring authentication flows and app entry points. The decision trees are genuinely helpful for navigating when to use Regular versus Clear glass variants or which text style fits your hierarchy. It's opinionated about doing design decisions before implementation, which is the right call. The conflict resolution section that explicitly maps design choices to accessibility and SwiftUI skills saves you from guessing which reference to consult first.
npx skills add https://github.com/charleswiltgen/axiom --skill axiom-design