�ng cho Tetris -->
    <link rel="stylesheet" href="css/tetris.css">
    <link rel="icon" href="favicon.png" type="image/png">
</head>

<body>
    <!-- Language Switcher (giữ nguyên) -->
    <div class="lang-switcher-container">
        <div class="lang-switcher btn-group" role="group" aria-label="Language selector">
            <button type="button" class="btn btn-outline-secondary lang-btn" data-lang="vi">VI</button>
            <button type="button" class="btn btn-outline-secondary lang-btn" data-lang