Nested Components demonstrates a minimal React application composed of three child components: Navbar, MainContent, and Footer, all rendered inside a parent App component. The code imports React and ReactDOM, using `ReactDOM.render` to mount the App into the `#root` div. Each child component returns simple JSX elements, such as a navigation link, a paragraph with Chinese text, and a footer heading, with styling defined in an external stylesheet. The example illustrates component nesting and basic UI structure without any data fetching or interactive behavior.