body {
            background-color: #1a1a1a;
            color: #ffffff;
            font-family: 'Arial', sans-serif;
            background-image: linear-gradient(rgba(0, 0, 0, 0.7), rgba(0, 0, 0, 0.7));
        }
        .quiz-container {
            background-color: #2d2d2d;
            border: 2px solid #4a4a4a;
            box-shadow: 0 0 15px rgba(128, 128, 128, 0.3);
        }
        .answer-btn {
            transition: all 0.3s ease;
        }
        .answer-btn:hover {
            background-color: #3d3d3d;
            transform: scale(1.02);
        }
        .correct {
            background-color: #2d4a2f !important;
        }
        .wrong {
            background-color: #4a1f1f !important;
        }
        .progress-bar {
            height: 10px;
            background-color: #4a4a4a;
            border-radius: 5px;
            overflow: hidden;
        }
        .progress-fill {
            height: 100%;
            background-color: #808080;
            transition: width 0.5s ease;
        }