body {
            background-color: #1a0f0f;
            color: #ffffff;
            font-family: 'Arial', sans-serif;
        }
        .quiz-container {
            background-color: #2d1f1f;
            border: 2px solid #4a2f2f;
            box-shadow: 0 0 15px rgba(139, 0, 0, 0.2);
        }
        .answer-btn {
            transition: all 0.3s ease;
        }
        .answer-btn:hover {
            background-color: #3d2828;
            transform: scale(1.02);
        }
        .correct {
            background-color: #2d4a2f !important;
        }
        .wrong {
            background-color: #4a1f1f !important;
        }
        .progress-bar {
            height: 10px;
            background-color: #4a2f2f;
            border-radius: 5px;
            overflow: hidden;
        }
        .progress-fill {
            height: 100%;
            background-color: #8b0000;
            transition: width 0.5s ease;
        }
        .shadow-effect {
            animation: shadowPulse 3s infinite;
        }
        @keyframes shadowPulse {
            0%, 100% { box-shadow: 0 0 15px rgba(139, 0, 0, 0.2); }
            50% { box-shadow: 0 0 25px rgba(139, 0, 0, 0.4); }
        }