Guardrails for building Japanese-ready web interfaces. Automatically enforces correct CJK typography (font stacks, line-height, kinsoku shori), Japanese form conventions (furigana fields, postal code auto-fill, Imperial era dates, confirmation screens), honorific-aware UX copy, seasonal color themes, accessibility (JIS X 8341-3), and production-ready CSS. Prevents common mistakes like using italic for emphasis, wrong name field order, and loading full CJK font files.