body {
            background: #121212;
            color: #ffffff;
            display: flex;
            align-items: center;
            justify-content: center;
            min-height: 100vh;
            font-family: 'Poppins', sans-serif;
            margin: 0;
            padding: 1rem;
        }

        .blinking-icon {
            text-align: center;
            margin-bottom: 1.5rem;
            animation: blink 1.2s infinite;
        }

        @keyframes blink {
            0%, 100% { opacity: 1; }
            50% { opacity: 0.3; }
        }

        .container-box {
            background: #1e1e1e;
            padding: 2.5rem 2rem;
            border-radius: 20px;
            box-shadow: 0 12px 30px rgba(0, 0, 0, 0.4);
            text-align: center;
            max-width: 480px;
            width: 100%;
        }

        h4 {
            font-weight: 600;
            color: #f1f1f1;
        }

        p {
            color: #cccccc;
            font-size: 0.95rem;
        }

        .btn-custom {
            font-size: 1.1rem;
            margin-top: 1.8rem;
            width: 100%;
            padding: 0.75rem;
            border-radius: 12px;
            background-color: #28a745;
            border: none;
            transition: background-color 0.3s ease;
        }

        .btn-custom:hover {
            background-color: #218838;
        }

        .alert {
            max-width: 480px;
            margin-top: 1.5rem;
        }