MARKS&WEB Style Design System (DESIGN.md, Japanese UI)

Design policy: A Japanese-born botanical skincare brand that champions "daily products." Its defining trait is a thoroughgoing monochrome composed solely of white, light gray, and dark gray #303030. Eliminating color, it expresses the honesty of "the material itself" through nothing but whitespace and typography. Decoration is virtually zero, shadows are zero, and corner radii are zero - Density: The product listing is EC-style, arranging dense, small text (14px card titles) in a grid. Body text uses 16px / line-height 1.8 with generous leading to ensure readability. A bilingual two-tier headi