ONIBUS COFFEE Style Design System (DESIGN.md, Japanese UI)

Design policy: Lay a warm ivory #f8f6f4 reminiscent of a roastery's paper bag across the entire base, and compose with 1px black rules and small text with widely opened letter spacing. Add no decoration whatsoever, and construct with only product photos (coffee bags on white backgrounds) and whitespace. A "subtractive craft EC" that uses no rounded corners, shadows, or filled buttons - Density: Low to medium density. The product grid is arranged in 4 columns, but while tightening with an 8px gutter, the cards themselves have no frames or shadows. Text is small at 12–18px, and instead breathes