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

Design policy: Light theme basis (#f5f5f5 surfaces + #000000 text), embodying cleanliness and sincerity. Product photography is used boldly in the hero, with a dark overlay (rgba(0,0,0,0.6)) ensuring readability. The brand color SHARP Red (#e6000d) is used at key points, functioning as an accent color - Density: Product categories are arranged neatly in a card grid, keeping information density at a moderate level. Body weight is thin at 300 (Light), giving an overall light and clean impression - Keywords: Clean & light, Noto Sans JP only, SHARP Red accent, product photography-centric, Nature T