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

Design policy: Extreme minimalism of pure white #ffffff × pure black #000000. Furniture and spatial photography take the lead, while the UI stays thoroughly in the background — a style unique to interior brands - Density: Large amounts of whitespace, composed of photography and minimal textual information. Information density is low; the whitespace itself is the brand expression - Keywords: Pure white and pure black monochrome, thin-stroke Latin/Japanese mixed typesetting with Source Sans 3 + Noto Sans JP, relaxed letter-spacing of 1px (≈0.07em), zero border radius, buttons reduced to "VIEW AL