Mẫu chương trình khung hệ vừa làm vừa học

/* Fallback styles for no-JS environments */ body { visibility: visible !important; } .css-loading { visibility: visible !important; } .d-none { display: none !important; } .container { max-width: 1320px; margin: 0 auto; padding: 0 15px; } .btn { padding: 8px 16px; background: #0d6efd; color: white; text-decoration: none; border-radius: 4px; display: inline-block; border: none; } .alert { padding: 12px; margin: 16px 0; border-radius: 4px; background: #f8f9fa; border: 1px solid #dee2e6; } .alert-warning { background: #fff3cd; border-color: #ffecb5; color: #664d03; }