html { color-scheme: light dark; }
body { margin: 0; min-height: 100vh; display: flex; align-items: center; justify-content: center;
       font-family: system-ui, sans-serif; background: Canvas; color: CanvasText; }
h1 { font-weight: 500; font-size: 1.5rem; padding: 0 16px; text-align: center; }