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

Design approach: An extremely bold, minimal EC composed solely of "Helvetica + uppercase + thin rules". CSS Custom Properties define --heading-text-transform: uppercase and --heading-letter-spacing: -0.02em as brand-wide conventions, unifying all headings with uppercase and tight tracking - Density: Large lookbook images take the lead; text plays a supporting role. EC functionality is built on Shopify with only minimal rules and buttons - Keywords: Helvetica, Bold, UPPERCASE, Negative letter-spacing, hybrid, bold, stoic, unadorned, photography-first, pure-black rules, white ground - Characteri