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

Design policy: A white base with teal green #00b6ac accents placed at key points, forming a clean, near-futuristic impression befitting an urban mobility service. Decoration is kept to a minimum, with a minimal composition that lets whitespace breathe - Density: Body text line-height is a standard 1.5. Headings stand large and dynamic with tight line-height 1.0. Information density is low to medium, with abundant white space - Keywords: Minimal, teal accent, Roobert's international tech feel, light weight, urban mobility - Characteristics: - Roobert (a geometric sans-serif by Display Foundry)