<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Popup</title>
<link rel="stylesheet" href="solution.css" />
</head>
<body>
<div id="popup-container">
<button id="open-modal">Click Me!</button>
<div class="popup-modal">
<p>Hey there!</p>
<button id="close-modal">X</button>
</div>
</div>
<script src="solution.js"></script>
</body>
</html>