* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  
  body {
    font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f5f7fa;
  }
  
  .container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
  }
  
  /* Page Management */
  .page {
    display: none;
    min-height: 100vh;
  }
  
  .page.active {
    display: block;
  }
  
  /* Cards */
  .card {
    background: white;
    border-radius: 12px;
    padding: 24px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    margin-bottom: 20px;
  }
  
  /* Buttons */
  .btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
  }
  
  .btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
  }
  
  .btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
  }
  
  .btn-outline {
    background: transparent;
    border: 2px solid #667eea;
    color: #667eea;
  }
  
  .btn-outline:hover {
    background: #667eea;
    color: white;
  }
  
  .btn-success {
    background: linear-gradient(135deg, #4caf50 0%, #45a049 100%);
    color: white;
  }
  
  .btn-success:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(76, 175, 80, 0.4);
  }
  
  .btn-large {
    padding: 16px 32px;
    font-size: 18px;
  }
  
  .btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
  }
  
  /* Landing Page */
  .header {
    text-align: center;
    margin-bottom: 40px;
  }
  
  .header h1 {
    font-size: 3rem;
    font-weight: 700;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 10px;
  }
  
  .header p {
    font-size: 1.2rem;
    color: #666;
    margin-bottom: 15px;
  }
  
  .badge {
    display: inline-block;
    background: linear-gradient(135deg, #ff6b6b 0%, #ee5a24 100%);
    color: white;
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 600;
  }
  
  .course-info h2 {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 20px;
    color: #333;
  }
  
  .icon {
    font-size: 1.5rem;
  }
  
  .info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-top: 20px;
  }
  
  .info-item {
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 15px;
    background: #f8f9fa;
    border-radius: 8px;
  }
  
  .info-item h3 {
    font-size: 1rem;
    color: #333;
    margin-bottom: 5px;
  }
  
  .info-item p {
    color: #666;
    font-size: 0.9rem;
  }
  
  .instructions h2 {
    margin-bottom: 20px;
    color: #333;
  }
  
  .instruction-list {
    display: flex;
    flex-direction: column;
    gap: 15px;
  }
  
  .instruction-item {
    display: flex;
    align-items: flex-start;
    gap: 15px;
  }
  
  .step-number {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    width: 30px;
    height: 30px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    flex-shrink: 0;
  }
  
  .start-section {
    text-align: center;
    margin-top: 40px;
  }
  
  .note {
    margin-top: 15px;
    color: #666;
    font-size: 0.9rem;
  }
  
  .quiz-info {
    margin-top: 10px;
    color: #667eea;
    font-weight: 600;
    font-size: 0.95rem;
  }
  
  /* Test Interface */
  .test-header {
    background: white;
    padding: 20px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 100;
  }
  
  .test-nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 15px;
  }
  
  .test-nav h2 {
    color: #333;
    font-size: 1.5rem;
  }
  
  .test-info {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 15px;
  }
  
  .timer {
    display: flex;
    align-items: center;
    gap: 8px;
    background: #ff6b6b;
    color: white;
    padding: 8px 16px;
    border-radius: 20px;
    font-weight: 600;
  }
  
  .question-badge {
    background: #667eea;
    color: white;
    padding: 8px 16px;
    border-radius: 20px;
    font-weight: 600;
  }
  
  .progress-bar {
    width: 100%;
    height: 6px;
    background: #e0e0e0;
    border-radius: 3px;
    overflow: hidden;
  }
  
  .progress-fill {
    height: 100%;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    transition: width 0.3s ease;
  }
  
  .test-content {
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: 30px;
    padding: 30px;
    max-width: 1400px;
    margin: 0 auto;
  }
  
  .question-navigator h3 {
    margin-bottom: 20px;
    color: #333;
  }
  
  .question-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 10px;
    margin-bottom: 20px;
  }
  
  .question-nav-btn {
    width: 40px;
    height: 40px;
    border: 2px solid #e0e0e0;
    background: white;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
  }
  
  .question-nav-btn:hover {
    border-color: #667eea;
    color: #667eea;
  }
  
  .question-nav-btn.current {
    background: #667eea;
    color: white;
    border-color: #667eea;
  }
  
  .question-nav-btn.answered {
    background: #4caf50;
    color: white;
    border-color: #4caf50;
  }
  
  .legend {
    display: flex;
    flex-direction: column;
    gap: 10px;
  }
  
  .legend-item {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 0.9rem;
  }
  
  .legend-color {
    width: 16px;
    height: 16px;
    border-radius: 4px;
  }
  
  .legend-color.answered {
    background: #4caf50;
  }
  
  .legend-color.unanswered {
    background: #e0e0e0;
  }
  
  .legend-color.current {
    background: #667eea;
  }
  
  .question-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 20px;
  }
  
  .question-header h3 {
    color: #333;
    font-size: 1.3rem;
  }
  
  .subject-badge {
    background: #ff6b6b;
    color: white;
    padding: 6px 12px;
    border-radius: 15px;
    font-size: 0.85rem;
    font-weight: 600;
  }
  
  .question-text {
    font-size: 1.1rem;
    line-height: 1.6;
    margin-bottom: 25px;
    color: #333;
  }
  
  .options {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 30px;
  }
  
  .option {
    display: flex;
    align-items: center;
    padding: 15px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
  }
  
  .option:hover {
    border-color: #667eea;
    background: #f8f9ff;
  }
  
  .option.selected {
    border-color: #667eea;
    background: #f8f9ff;
  }
  
  .option input[type="radio"] {
    margin-right: 15px;
    transform: scale(1.2);
  }
  
  .option-label {
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
    width: 100%;
  }
  
  .option-letter {
    font-weight: 600;
    color: #667eea;
    min-width: 25px;
  }
  
  .question-controls {
    display: flex;
    align-items: center;
    justify-content: space-between;
  }
  
  .control-buttons {
    display: flex;
    gap: 15px;
  }
  
  /* Results Page */
  .results-header {
    text-align: center;
    margin-bottom: 40px;
  }
  
  .results-header h1 {
    font-size: 2.5rem;
    color: #333;
    margin-bottom: 10px;
  }
  
  .score-overview {
    text-align: center;
    margin-bottom: 40px;
  }
  
  .grade-circle {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
    font-size: 3rem;
    font-weight: 700;
    color: white;
  }
  
  .grade-circle.grade-a {
    background: linear-gradient(135deg, #4caf50 0%, #45a049 100%);
  }
  
  .grade-circle.grade-b {
    background: linear-gradient(135deg, #2196f3 0%, #1976d2 100%);
  }
  
  .grade-circle.grade-c {
    background: linear-gradient(135deg, #ff9800 0%, #f57c00 100%);
  }
  
  .grade-circle.grade-d {
    background: linear-gradient(135deg, #ff5722 0%, #d84315 100%);
  }
  
  .grade-circle.grade-f {
    background: linear-gradient(135deg, #f44336 0%, #d32f2f 100%);
  }
  
  .score-overview h2 {
    font-size: 2rem;
    margin-bottom: 20px;
    color: #333;
  }
  
  .score-progress {
    max-width: 400px;
    margin: 0 auto;
  }
  
  .score-progress .progress-bar {
    height: 12px;
    margin-bottom: 10px;
  }
  
  .analytics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 40px;
  }
  
  .analytics-card {
    background: white;
    border-radius: 12px;
    padding: 24px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    border-left: 4px solid #667eea;
  }
  
  .analytics-card.correct {
    border-left-color: #4caf50;
  }
  
  .analytics-card.incorrect {
    border-left-color: #f44336;
  }
  
  .analytics-card.skipped {
    border-left-color: #ff9800;
  }
  
  .analytics-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
  }
  
  .analytics-text p {
    color: #666;
    margin-bottom: 5px;
  }
  
  .analytics-text h3 {
    font-size: 2rem;
    color: #333;
  }
  
  .analytics-icon {
    font-size: 2rem;
    opacity: 0.7;
  }
  
  .performance-breakdown h3 {
    margin-bottom: 20px;
    color: #333;
  }
  
  .breakdown-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 15px;
  }
  
  .breakdown-progress {
    display: flex;
    align-items: center;
    gap: 15px;
    flex: 1;
    max-width: 300px;
  }
  
  .breakdown-progress .progress-bar {
    flex: 1;
    height: 8px;
  }
  
  .time-badge {
    background: #667eea;
    color: white;
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 0.9rem;
    font-weight: 600;
  }
  
  .action-buttons {
    display: flex;
    gap: 20px;
    justify-content: center;
    margin-bottom: 40px;
  }
  
  .feedback {
    text-align: center;
    padding: 30px;
    border-radius: 12px;
  }
  
  .feedback.success {
    background: linear-gradient(135deg, #d4edda 0%, #c3e6cb 100%);
    border: 1px solid #c3e6cb;
    color: #155724;
  }
  
  .feedback.good {
    background: linear-gradient(135deg, #cce5ff 0%, #b3d9ff 100%);
    border: 1px solid #b3d9ff;
    color: #004085;
  }
  
  .feedback.needs-improvement {
    background: linear-gradient(135deg, #fff3cd 0%, #ffeaa7 100%);
    border: 1px solid #ffeaa7;
    color: #856404;
  }
  
  .warning {
    color: #856404;
  }
  
  /* Review Page */
  .review-header {
    margin-bottom: 40px;
  }
  
  .review-header h1 {
    font-size: 2.5rem;
    color: #333;
    margin-bottom: 20px;
  }
  
  .review-controls {
    display: flex;
    gap: 15px;
    margin-bottom: 20px;
  }
  
  .review-summary {
    display: flex;
    gap: 20px;
    align-items: center;
    flex-wrap: wrap;
  }
  
  .score-badge {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 8px 16px;
    border-radius: 20px;
    font-weight: 600;
  }
  
  .stat-item {
    background: #f8f9fa;
    padding: 8px 16px;
    border-radius: 20px;
    font-weight: 600;
  }
  
  .review-questions {
    display: flex;
    flex-direction: column;
    gap: 30px;
    margin-bottom: 40px;
  }
  
  .review-question {
    background: white;
    border-radius: 12px;
    padding: 24px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    border-left: 4px solid #e0e0e0;
  }
  
  .review-question.correct {
    border-left-color: #4caf50;
  }
  
  .review-question.incorrect {
    border-left-color: #f44336;
  }
  
  .review-question.skipped {
    border-left-color: #ff9800;
  }
  
  .review-question-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 15px;
  }
  
  .review-question-title {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 600;
    color: #333;
  }
  
  .status-badge {
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 0.85rem;
    font-weight: 600;
    text-transform: capitalize;
  }
  
  .status-badge.correct {
    background: #d4edda;
    color: #155724;
  }
  
  .status-badge.incorrect {
    background: #f8d7da;
    color: #721c24;
  }
  
  .status-badge.skipped {
    background: #fff3cd;
    color: #856404;
  }
  
  .review-question-text {
    font-size: 1.1rem;
    line-height: 1.6;
    margin-bottom: 20px;
    color: #333;
  }
  
  .review-options {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-bottom: 20px;
  }
  
  .review-option {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 15px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
  }
  
  .review-option.correct-answer {
    border-color: #4caf50;
    background: #f1f8e9;
  }
  
  .review-option.user-answer {
    border-color: #f44336;
    background: #ffebee;
  }
  
  .review-option.correct-user-answer {
    border-color: #4caf50;
    background: #e8f5e8;
  }
  
  .option-badges {
    display: flex;
    gap: 8px;
  }
  
  .option-badge {
    padding: 2px 8px;
    border-radius: 10px;
    font-size: 0.75rem;
    font-weight: 600;
  }
  
  .option-badge.correct {
    background: #4caf50;
    color: white;
  }
  
  .option-badge.user {
    background: #f44336;
    color: white;
  }
  
  .option-badge.user-correct {
    background: #4caf50;
    color: white;
  }
  
  .skipped-notice {
    background: #fff3cd;
    border: 1px solid #ffeaa7;
    color: #856404;
    padding: 15px;
    border-radius: 8px;
    margin-bottom: 15px;
  }
  
  .explanation {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 8px;
    border-left: 4px solid #667eea;
  }
  
  .explanation h4 {
    color: #333;
    margin-bottom: 10px;
  }
  
  .explanation p {
    color: #666;
    line-height: 1.6;
  }
  
  .review-footer {
    text-align: center;
    margin-top: 40px;
  }
  
  .review-footer h3 {
    color: #333;
    margin-bottom: 15px;
  }
  
  .footer-buttons {
    display: flex;
    gap: 15px;
    justify-content: center;
    margin-top: 20px;
  }
  
  /* Modal */
  .modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    align-items: center;
    justify-content: center;
  }
  
  .modal.active {
    display: flex;
  }
  
  .modal-content {
    background: white;
    padding: 30px;
    border-radius: 12px;
    max-width: 500px;
    width: 90%;
    text-align: center;
  }
  
  .modal-content h3 {
    color: #333;
    margin-bottom: 15px;
  }
  
  .modal-content p {
    color: #666;
    margin-bottom: 25px;
    line-height: 1.6;
  }
  
  .modal-buttons {
    display: flex;
    gap: 15px;
    justify-content: center;
  }
  
  /* Responsive Design */
  @media (max-width: 768px) {
    .container {
      padding: 15px;
    }
  
    .header h1 {
      font-size: 2rem;
    }
  
    .test-content {
      grid-template-columns: 1fr;
      gap: 20px;
      padding: 20px;
    }
  
    .question-navigator {
      order: 2;
    }
  
    .question-content {
      order: 1;
    }
  
    .analytics-grid {
      grid-template-columns: 1fr;
    }
  
    .action-buttons {
      flex-direction: column;
      align-items: center;
    }
  
    .review-controls {
      flex-direction: column;
    }
  
    .review-summary {
      justify-content: center;
    }
  
    .modal-buttons {
      flex-direction: column;
    }
  
    .footer-buttons {
      flex-direction: column;
      align-items: center;
    }
  }
  
  @media (max-width: 480px) {
    .info-grid {
      grid-template-columns: 1fr;
    }
  
    .question-grid {
      grid-template-columns: repeat(4, 1fr);
    }
  
    .test-info {
      flex-direction: column;
      gap: 10px;
      align-items: flex-start;
    }
  
    .question-controls {
      flex-direction: column;
      gap: 15px;
    }
  
    .control-buttons {
      width: 100%;
      justify-content: space-between;
    }
  }
  
  /* WhatsApp Popup Styles */
  .whatsapp-popup {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.6);
    z-index: 2000;
    align-items: center;
    justify-content: center;
    backdrop-filter: blur(2px);
    animation: fadeIn 0.3s ease-out;
  }
  
  .whatsapp-popup.active {
    display: flex;
  }
  
  .whatsapp-popup-content {
    background: white;
    border-radius: 16px;
    max-width: 420px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
    position: relative;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    animation: slideUp 0.4s ease-out;
  }
  
  .whatsapp-close-btn {
    position: absolute;
    top: 15px;
    right: 15px;
    background: #f5f5f5;
    border: none;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s ease;
    z-index: 1;
  }
  
  .whatsapp-close-btn:hover {
    background: #e0e0e0;
    transform: scale(1.1);
  }
  
  .whatsapp-close-btn i {
    color: #666;
    font-size: 14px;
  }
  
  .whatsapp-popup-header {
    text-align: center;
    padding: 30px 30px 20px;
    background: linear-gradient(135deg, #25d366 0%, #128c7e 100%);
    color: white;
    border-radius: 16px 16px 0 0;
  }
  
  .whatsapp-icon {
    width: 60px;
    height: 60px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 15px;
    backdrop-filter: blur(10px);
  }
  
  .whatsapp-icon i {
    font-size: 28px;
    color: white;
  }
  
  .whatsapp-popup-header h3 {
    margin: 0;
    font-size: 1.4rem;
    font-weight: 600;
  }
  
  .whatsapp-popup-body {
    padding: 25px 30px;
  }
  
  .whatsapp-popup-body p {
    color: #555;
    line-height: 1.6;
    margin-bottom: 20px;
    text-align: center;
  }
  
  .whatsapp-benefits {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
    margin-bottom: 10px;
  }
  
  .benefit-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 12px;
    background: #f8f9fa;
    border-radius: 8px;
    transition: all 0.3s ease;
  }
  
  .benefit-item:hover {
    background: #e9ecef;
    transform: translateY(-2px);
  }
  
  .benefit-item i {
    color: #25d366;
    font-size: 16px;
    width: 20px;
    text-align: center;
  }
  
  .benefit-item span {
    color: #333;
    font-size: 0.9rem;
    font-weight: 500;
  }
  
  .whatsapp-popup-footer {
    padding: 0 30px 30px;
    display: flex;
    flex-direction: column;
    gap: 12px;
  }
  
  .btn-whatsapp {
    background: linear-gradient(135deg, #25d366 0%, #128c7e 100%);
    color: white;
    border: none;
    padding: 14px 24px;
    border-radius: 10px;
    font-weight: 600;
    font-size: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
  }
  
  .btn-whatsapp:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(37, 211, 102, 0.4);
  }
  
  .btn-whatsapp i {
    font-size: 18px;
  }
  
  .btn-outline-small {
    background: transparent;
    border: 2px solid #e0e0e0;
    color: #666;
    padding: 10px 20px;
    border-radius: 8px;
    font-size: 14px;
    cursor: pointer;
    transition: all 0.3s ease;
  }
  
  .btn-outline-small:hover {
    border-color: #ccc;
    background: #f8f9fa;
  }
  
  /* Animations */
  @keyframes fadeIn {
    from {
      opacity: 0;
    }
    to {
      opacity: 1;
    }
  }
  
  @keyframes slideUp {
    from {
      opacity: 0;
      transform: translateY(30px) scale(0.95);
    }
    to {
      opacity: 1;
      transform: translateY(0) scale(1);
    }
  }
  
  /* Responsive Design */
  @media (max-width: 480px) {
    .whatsapp-popup-content {
      width: 95%;
      margin: 20px;
    }
  
    .whatsapp-popup-header,
    .whatsapp-popup-body,
    .whatsapp-popup-footer {
      padding-left: 20px;
      padding-right: 20px;
    }
  
    .whatsapp-benefits {
      grid-template-columns: 1fr;
      gap: 10px;
    }
  
    .benefit-item {
      padding: 10px;
    }
  
    .whatsapp-popup-header h3 {
      font-size: 1.2rem;
    }
  
    .whatsapp-icon {
      width: 50px;
      height: 50px;
    }
  
    .whatsapp-icon i {
      font-size: 24px;
    }
  }
  
  @media (max-width: 360px) {
    .whatsapp-popup-footer {
      padding-bottom: 20px;
    }
  
    .btn-whatsapp {
      padding: 12px 20px;
      font-size: 15px;
    }
  }