LUPICIA Style Design System (DESIGN.md, Japanese UI)

Design policy: A design unified in warm natural tones, coexisting the quietness of the tea ceremony with modern refinement. Restrained decoration, conveying the world of tea through content whitespace and earthy colors - Density: Body text 16px / line-height 1.6–1.8. A relaxed, media-style layout. Rather than packing in information, it prioritizes the comfort of reading - Keywords: Warm neutral, earth colors, whitespace, premium feel, tea-ceremony minimalism - Characteristics: - No CSS Custom Properties — built with conventional CSS (classic CSS) - Latin-script-first font stack: Open Sans at t