* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  
  body {
    font-family: 'Microsoft YaHei', 'SimSun', 'PingFang SC', -apple-system, BlinkMacSystemFont, Arial, sans-serif;
    line-height: 1.8;
    color: #333;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    padding: 0;
    margin: 0;
  }
  
  .wrapper {
    max-width: 1200px;
    margin: 20px auto;
    background: white;
    border-radius: 12px;
    box-shadow: 0 10px 40px rgba(0,0,0,0.1);
    overflow: hidden;
  }
  
  header#title-block-header {
    background: linear-gradient(135deg, #c41230 0%, #8b0000 100%);
    color: white !important;
    padding: 50px 40px;
    text-align: center;
    margin: 0 !important;
  }
  
  h1.title {
    font-size: 2.5em !important;
    color: white !important;
    margin: 0 !important;
    padding: 0 !important;
    border: none !important;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
  }
  
  .content-area {
    padding: 40px;
  }
  
  /* New Loading Spinner Style */
  .loading-spinner {
    border: 5px solid #f3f3f3;
    border-top: 5px solid #c41230;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    animation: spin 1s linear infinite;
    margin: 50px auto;
  }
  
  @keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
  }
  
  /* Filter Info Bar */
  #filterInfo {
    text-align: center; 
    padding: 15px; 
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); 
    color: white; 
    border-radius: 8px; 
    margin-bottom: 20px; 
    font-size: 1.1em; 
    font-weight: bold; 
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    display: none; /* Initially hidden */
  }
  
  h3 {
    font-size: 2em;
    color: #c41230;
    margin: 60px 0 30px 0;
    padding: 20px 30px;
    background: linear-gradient(135deg, #fff5f5 0%, #ffe5e5 100%);
    border-left: 6px solid #c41230;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(196,18,48,0.1);
  }
  
  /* --- Question Styles --- */
  
  .question-item {
    background: #ffffff;
    border-left: 4px solid #c41230;
    padding: 25px;
    margin-bottom: 20px;
    border-radius: 12px;
    box-shadow: 0 3px 12px rgba(0,0,0,0.08);
    transition: all 0.3s ease;
  }
  
  .question-item:hover {
    box-shadow: 0 6px 24px rgba(196,18,48,0.2);
    transform: translateY(-2px);
  }
  
  .question-number {
    display: inline-block;
    background: linear-gradient(135deg, #c41230 0%, #8b0000 100%);
    color: white;
    padding: 6px 16px;
    border-radius: 20px;
    font-weight: bold;
    font-size: 0.9em;
    margin-bottom: 12px;
    box-shadow: 0 2px 6px rgba(196,18,48,0.3);
  }
  
  .question-title {
    font-size: 1.1em;
    line-height: 1.8;
    color: #2c3e50;
    margin: 12px 0 16px 0;
    font-weight: 500;
  }
  
  mark {
    background-color: #ffc107;
    padding: 0 2px;
    border-radius: 3px;
  }
  
  .question-options {
    margin: 16px 0;
    padding-left: 0;
  }
  
  .option-item {
    display: flex;
    align-items: flex-start;
    padding: 12px 16px;
    margin: 8px 0;
    background: #f8f9fa;
    border-radius: 8px;
    border-left: 3px solid #dee2e6;
    transition: all 0.2s ease;
  }
  
  .option-item.correct {
    background: #d4edda;
    border-left: 4px solid #28a745;
    box-shadow: 0 2px 8px rgba(40,167,69,0.15);
  }
  
  .option-label {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 32px;
    height: 32px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: 50%;
    font-weight: bold;
    margin-right: 12px;
    flex-shrink: 0;
    font-size: 0.9em;
    box-shadow: 0 2px 6px rgba(102,126,234,0.3);
  }
  
  .option-item.correct .option-label {
    background: linear-gradient(135deg, #28a745 0%, #20c997 100%);
    box-shadow: 0 2px 8px rgba(40,167,69,0.4);
  }
  
  .option-text {
    flex: 1;
    line-height: 1.6;
    color: #34495e;
    padding-top: 4px;
  }
  
  .question-answer {
    display: inline-block;
    padding: 8px 20px;
    border-radius: 20px;
    font-weight: bold;
    margin-top: 12px;
    font-size: 0.95em;
  }
  
  .answer-correct {
      background: #d4edda; color: #155724; border: 2px solid #28a745;
  }
  .answer-wrong {
      background: #f8d7da; color: #721c24; border: 2px solid #dc3545;
  }
  .answer-fill {
      margin-top: 12px;
  }
  .answer-fill-tag {
      color: #667eea; font-weight: bold; margin-right: 8px;
  }
  .answer-fill-item {
      display: inline-block; background: #e3f2fd; color: #1565c0; padding: 4px 12px; border-radius: 15px; margin: 2px 4px; font-weight: bold; border: 1px solid #2196f3;
  }
  
  
  /* --- Other UI elements --- */
  
  .back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background: #c41230;
    color: white;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    border: none;
    cursor: pointer;
    display: none;
    align-items: center;
    justify-content: center;
    font-size: 1.5em;
    box-shadow: 0 4px 12px rgba(196,18,48,0.4);
    transition: all 0.3s ease;
    z-index: 1000;
  }
  
  .back-to-top:hover {
    background: #a00f28;
    transform: translateY(-5px);
  }
  
  .back-to-top.show {
    display: flex !important;
  }
  
  .font-controls {
    position: fixed;
    bottom: 90px;
    right: 30px;
    display: flex;
    flex-direction: column;
    gap: 10px;
    z-index: 1000;
  }
  
  .font-btn {
    background: #667eea;
    color: white;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.3em;
    font-weight: bold;
    box-shadow: 0 4px 12px rgba(102,126,234,0.4);
    transition: all 0.3s ease;
  }
  
  .font-btn:hover {
    background: #5568d3;
    transform: scale(1.1);
  }
  
  .font-btn:active {
    transform: scale(0.95);
  }
  
  .position-toast {
    position: fixed;
    top: 80px;
    left: 50%;
    transform: translateX(-50%);
    background: linear-gradient(135deg, #43e97b 0%, #38f9d7 100%);
    color: white;
    padding: 15px 30px;
    border-radius: 25px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.2);
    z-index: 1001;
    display: none;
    font-weight: bold;
    animation: slideDown 0.3s ease;
  }
  
  @keyframes slideDown {
    from { opacity: 0; transform: translateX(-50%) translateY(-20px); }
    to { opacity: 1; transform: translateX(-50%) translateY(0); }
  }
  
  .position-toast.show {
    display: block;
  }
  
  .search-container {
    position: sticky;
    top: 0;
    background: white;
    padding: 20px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    z-index: 100;
    margin: 0 -40px 20px -40px;
  }
  
  .search-box {
    display: flex;
    gap: 10px;
    max-width: 800px;
    margin: 0 auto;
  }
  
  .search-input {
    flex: 1;
    padding: 12px 20px;
    border: 2px solid #dee2e6;
    border-radius: 25px;
    font-size: 1em;
    transition: all 0.3s ease;
  }
  
  .search-input:focus {
    outline: none;
    border-color: #c41230;
    box-shadow: 0 0 0 3px rgba(196,18,48,0.1);
  }
  
  .search-btn {
    padding: 12px 30px;
    background: #c41230;
    color: white;
    border: none;
    border-radius: 25px;
    cursor: pointer;
    font-size: 1em;
    font-weight: bold;
    transition: all 0.3s ease;
  }
  
  .search-btn:hover {
    background: #a00f28;
    transform: scale(1.05);
  }
  
  .search-btn.secondary {
    background: #6c757d;
  }
  
  .search-btn.secondary:hover {
    background: #5a6268;
  }
  
  .stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
    padding: 20px 0;
  }
  
  .stat-card {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    padding: 25px;
    border-radius: 10px;
    color: white;
    text-align: center;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    cursor: pointer;
    transition: all 0.3s ease;
    border: 3px solid transparent;
  }
  
  .stat-card:hover {
    transform: translateY(-8px) scale(1.05);
    box-shadow: 0 8px 25px rgba(0,0,0,0.2);
  }
  
  .stat-card.active {
    border: 3px solid #fff;
    box-shadow: 0 8px 30px rgba(0,0,0,0.3);
    transform: scale(1.08);
  }
  
  .stat-number {
    font-size: 2.5em;
    font-weight: bold;
    display: block;
  }
  
  .stat-label {
    font-size: 1em;
    opacity: 0.9;
    margin-top: 5px;
  }
  
  footer {
    background: #2c3e50;
    color: white;
    text-align: center;
    padding: 30px;
    margin: 40px -40px -40px -40px;
  }
  
  /* --- Media Queries for Responsiveness --- */
  @media (max-width: 768px) {
    /* ... (All original media queries are kept here) ... */
    body { padding: 0; }
    .wrapper { margin: 0; border-radius: 0; }
    .content-area { padding: 15px; }
    header#title-block-header { padding: 30px 20px; }
    h1.title { font-size: 1.6em !important; }
    .search-container { margin: 0 -15px 15px -15px; padding: 15px; }
    .search-box { flex-direction: column; gap: 10px; }
    .search-input { width: 100%; font-size: 16px; }
    .search-btn { width: 100%; padding: 14px 30px; font-size: 1em; }
    .stats { grid-template-columns: repeat(2, 1fr); gap: 12px; padding: 10px 0; }
    .stat-card { padding: 18px 15px; }
    .stat-number { font-size: 2em; }
    .stat-label { font-size: 0.9em; }
    h3 { font-size: 1.5em; margin: 40px 0 20px 0; padding: 15px 20px; }
    .question-item { padding: 18px; margin-bottom: 15px; }
    .question-number { font-size: 0.85em; padding: 5px 12px; }
    .question-title { font-size: 1em; line-height: 1.7; }
    .option-item { padding: 10px 12px; margin: 6px 0; }
    .option-item.correct { border-left: 3px solid #28a745; }
    .option-label { min-width: 28px; height: 28px; font-size: 0.85em; margin-right: 10px; }
    .option-text { font-size: 0.95em; }
    .question-answer { font-size: 0.9em; padding: 6px 16px; }
    .back-to-top { width: 45px; height: 45px; bottom: 20px; right: 20px; font-size: 1.3em; }
    .font-controls { bottom: 75px; right: 20px; gap: 8px; }
    .font-btn { width: 45px; height: 45px; font-size: 1.2em; }
    .position-toast { top: 60px; padding: 12px 20px; font-size: 0.9em; max-width: 90%; }
    footer { margin: 30px -15px -15px -15px; padding: 25px 15px; font-size: 0.9em; }
    .stat-card:active { transform: scale(0.95); }
    h3 { margin: 30px -15px 20px -15px; padding: 12px 15px; border-radius: 0; }
  }
  
  @media (max-width: 480px) {
    h1.title { font-size: 1.4em !important; }
    .stats { grid-template-columns: 1fr; gap: 10px; }
    .stat-card { padding: 15px; }
    .stat-number { font-size: 1.8em; }
  }
  
  @media (max-width: 768px) and (orientation: landscape) {
    header#title-block-header { padding: 20px; }
    h1.title { font-size: 1.3em !important; }
    .stats { grid-template-columns: repeat(4, 1fr); gap: 8px; }
    .stat-card { padding: 12px 8px; }
    .stat-number { font-size: 1.5em; }
    .stat-label { font-size: 0.75em; }
  }