Tokyo Opera City Art Gallery Style Design System (DESIGN.md, Japanese UI)

Design policy: Uses zero web fonts. A museum site that relies entirely on the OS-standard Yu Gothic typeface, does not touch letter-spacing, and draws its navigation lines with a single orange color - Density: Medium. A 1100px container centered, with dotted rules dividing sections on a white background - Keywords: Yu Gothic, letter-spacing normal, no palt, orange #e46a00, cyan #04a7c4, 2px borders