JR East (JR East) Style Design System (DESIGN.md, Japanese UI)

Design policy: A practical, utility-first design that prioritizes the functionality and trustworthiness expected of railway and transportation infrastructure. A brand color system themed on nature and greenery achieves both a sense of security and approachability - Density: Medium to high density. Efficiently arranges large amounts of information such as service status, route search, and area selection. Organized with card-based UI - Keywords: Trust, functional, nature, green, infrastructure - Characteristics: Uses #202020 rather than pure black (#000000). The most distinctive feature is a gre