:root{--color-bg:#b4b4b4;--color-surface:#fff;--color-border:#e5e7eb;--color-text:#111;--color-muted:#a3a3a3;--color-primary:#2563eb;--radius-md:12px;--space-md:16px}html,body{background:var(--color-bg);color:var(--color-text);margin:0;padding:0;font-family:Segoe UI,Arial,sans-serif}*{box-sizing:border-box}