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

Design policy: A quiet editorial composition built only from a warm off-white (parchment) base reminiscent of tree bark and reclaimed wood, pure black text, and ultra-thin rules. Photography and generous whitespace take center stage, and the UI commits to zero border-radius and zero decoration. - Density: Low to medium density. Small text (13–14px baseline) is placed with wide line spacing, and areas are divided not by surfaces but by whitespace and rules. - Keywords: Botanical / Parchment / Editorial / Minimal / Warmth - Shape language: All surfaces, buttons, and input fields use border-radiu