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

Design philosophy: A lifestyle and interior brand from Japan. It offers curtains, furniture, kitchenware, and household goods, with the motto "simple and long-lasting." Its distinguishing feature is a bilingual font system combining Gothic Medium BBB (Morisawa Gothic) + Gill Sans Nova — pairing a delicate gothic typeface for Japanese with a humanist sans-serif for English to express a refined yet understated worldview. The color scheme stays strictly within neutral tones of warm gray and copper, excluding flashy colors - Density: An e-commerce site with generous whitespace. The most distinctiv