:root{--color-bg:#0d1117;--color-surface:#161b22;--color-border:#30363d;--color-text:#e6edf3;--color-muted:#8d96a0;--color-accent:#1f6feb;--color-warning:#d29922;--color-success:#2ea043;--color-danger:#f85149}*{box-sizing:border-box}body{background:var(--color-bg);color:var(--color-text);margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif}.app-shell{max-width:480px;min-height:100dvh;margin:0 auto}.offline-banner{z-index:10;background:var(--color-warning);color:#1c1304;text-align:center;padding:8px 16px;font-size:13px;font-weight:600;position:sticky;top:0}