Pen Online Style Design System (DESIGN.md, Japanese UI)

Design policy: A monochrome editorial built on pure white #ffffff × pure black #000000. The authority of the magazine brand is expressed through a paid-font mix of Optima Nova LT Pro and FOT-Tsukushi Gothic Pr5 D. - Density: Structured on a multi-column grid like a magazine's column layout. Letter-spacing is intentionally set wide to reproduce the dignity of magazine typesetting. - Keywords: Monochrome, mixed typesetting of Optima Nova LT Pro (Latin) + FOT-Tsukushi Gothic Pr5 D (Japanese), a broad letter-spacing design ranging from 0.04 to 0.17em, palt applied across the board, only pure white