HTML <div class="container"><h1>Hello, Playground!</h1><button id="myButton" class="demo-btn">Click Me</button></div> CSS .demo-btn { background: #3b82f6; color: white; padding: 8px 16px; border: none; border-radius: 8px; cursor: pointer; } .demo-btn:hover { background: #2563eb; } JavaScript document.getElementById('myButton')?.addEventListener('click', () => { alert('Button clicked!'); });

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