React Js Conditional Rendering

<!DOCTYPE html>
<html>

<body>
    <div id="app"></div>
    <script type="text/babel">
        const { useState, useEffect } = React;
        function App() {
            const [user, setUser] = useState(null);

// Simulating an asynchronous user data fetch
            useEffect(() => {
                setTimeout(() => {
                    setUser({ name: 'John Doe', isAdmin: true });
                }, 2000);
            }, []);

return (
                <div className='container'>
                    <h3>React Js Conditonal Rendering</h3>
                    {user && (
                        <div>
                            <h1>Welcome, {user.name}!</h1>
                            {user.isAdmin && <p className='admin-privileges '>You have admin privileges.</p>}
                        </div>
                    )}
                    {!user && <p cllasName='loading'>Loading user data...</p>}

</div >
            );
        }

ReactDOM.render(<App />, document.getElementById("app"));
    </script>
    <style>
        * {
            box-sizing: border-box;
        }

body {
            font-family: Arial, sans-serif;
            margin: 0;
            padding: 0;
        }

.container {
            margin: 0 auto;
            width: 600px;
            text-align: center;
            box-shadow: 0 1px 2px 0 rgba(0, 0, 0, 0.12), 0 2px 4px 0 rgba(0, 0, 0, 0.24);
            padding: 20px;
        }

h3 {
            margin-bottom: 20px;
            color: #333;
        }

h1 {
            font-size: 24px;
            margin-bottom: 10px;
        }

p {
            font-size: 16px;
            color: #666;
        }

.loading {
            font-style: italic;
            color: #999;
        }

.admin-privileges {
            font-weight: bold;
            color: #0f8;
        }
    </style>
</body>

</html>