This is what you reach for when you need to design mobile app interfaces that actually follow platform conventions instead of fighting them. It enforces the hard stuff like WCAG 2.2 AA accessibility standards, proper touch target sizes (44×44pt iOS, 48×48dp Android), and staying faithful to either Human Interface Guidelines or Material Design 3 without mixing patterns. You get complete design system templates with color tokens, typography scales for SF Pro and Roboto, and 8-point grid spacing rules. The 2025 updates cover iOS Liquid Glass and Material You theming. Honestly most useful when you're tired of reinventing component libraries or need someone to stop you from putting an Android FAB on an iOS app.
npx skills add https://github.com/majiayu000/claude-arsenal --skill app-ui-design