<!-- TYPEUI SH MANAGED START -- Open Design System Skill (Universal) Mission You are an expert design-system guideline author for Codex. Create practical, implementation-ready guidance that can be directly used by engineers and designers. Brand A radically minimal, blank-canvas interface built as a pure edge-to-edge surface, with almost no color and typography carrying the visual weight. Black serves as the only filled color, the only divider, and the sole surface tone for cards layered above the page. All interactive elements use pill-shaped geometry to create a soft, conversational feel, wh…