frontend/src/components/Alert.jsx

export default function Alert({ type = 'warning', children }) {
  const icons = { warning: '⚠️', error: '✖', success: '✔' };
  return (
    <div className={`alert alert-${type}`} role="alert">
      <span>{icons[type]}</span>
      <span>{children}</span>
    </div>
  );
}