index.html

<!DOCTYPE html>
<html>
<head>
    <title>Boss Game</title>
    <script src="https://cdn.jsdelivr.net/npm/phaser@3.55.2/dist/phaser.min.js"></script>
    <script src="game.js"></script>
    <style>
        body {
            margin: 0;
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
            background-color: #333;
        }
    </style>
</head>
<body>
</body>
</html>