<h1>Introduction to React.js</h1>
<p>React is a JavaScript library for building user interfaces, particularly single-page applications.</p>
<h2>Key Concepts</h2>
<ul>
    <li><strong>Components:</strong> Reusable, self-contained pieces of code</li>
    <li><strong>Props:</strong> Data passed to components</li>
    <li><strong>State:</strong> Internal data storage within a component</li>
    <li><strong>JSX:</strong> JavaScript XML syntax</li>
</ul>
<h2>Creating a Component</h2>
<pre><code>import React from 'react';

function Welcome(props) {
    return &lt;h1&gt;Hello, {props.name}&lt;/h1&gt;;
}

export default Welcome;</code></pre>