This example shows a simple interactive menu built with React, where a user can choose between two display options ("junto" or "separado") via a dropdown selector. The selected value is stored in React state using the `useState` hook and logged to the console, while the `Dropdown` component renders a native HTML `<select>` element and propagates changes through a callback. The code uses ReactDOM to mount the app, and relies on React 16.13.1 and ReactDOM from unpkg CDN. No external visualization library is involved; the focus is on state-driven UI updates.