/* Global Reset & Yellow-Black Theme Definitions */
    :root {
      --primary-yellow: #FFD600;
      --primary-yellow-hover: #F5C400;
      --accent-yellow-light: #FFFDE7;
      --accent-yellow-glow: rgba(255, 214, 0, 0.25);
      --text-dark: #111827;
      --text-muted: #4B5563;
      --text-light: #6B7280;
      --bg-canvas: #FAFAFA;
      --bg-card: #FFFFFF;
      --border-color: #E5E7EB;
      --border-accent: #FFE566;
      --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.04);
      --shadow-md: 0 6px 16px rgba(0, 0, 0, 0.06);
      --shadow-lg: 0 12px 28px rgba(0, 0, 0, 0.08);
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-lg: 18px;
      --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
    }

    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    html {
      scroll-behavior: smooth;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
      background-color: var(--bg-canvas);
      color: var(--text-dark);
      line-height: 1.6;
    }

    body {
      overflow-x: hidden;
    }

    a {
      color: inherit;
      text-decoration: none;
      transition: var(--transition);
    }

    /* Container Utility */
    .container {
      width: 100%;
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 20px;
    }

    /* Header & Navigation */
    header.site-header {
      position: sticky;
      top: 0;
      z-index: 1000;
      background-color: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(10px);
      border-bottom: 1px solid var(--border-color);
      box-shadow: var(--shadow-sm);
    }

    .nav-wrapper {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }

    .brand-logo {
      display: flex;
      align-items: center;
      gap: 12px;
    }

    .ai-page-logo {
      max-height: 42px;
      width: auto;
      object-fit: contain;
    }

    .nav-links {
      display: flex;
      gap: 0; /* Strictly required gap: 0 */
      list-style: none;
      align-items: center;
    }

    .nav-links li a {
      padding: 8px 14px;
      font-size: 15px;
      font-weight: 500;
      color: var(--text-dark);
      border-radius: var(--radius-sm);
      display: inline-block;
    }

    .nav-links li a:hover {
      background-color: var(--primary-yellow);
      color: #000;
    }

    .header-actions {
      display: flex;
      align-items: center;
      gap: 12px;
    }

    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 10px 22px;
      font-size: 15px;
      font-weight: 600;
      border-radius: 30px;
      cursor: pointer;
      border: none;
      transition: var(--transition);
      white-space: nowrap;
    }

    .btn-yellow {
      background-color: var(--primary-yellow);
      color: #000000;
      box-shadow: 0 4px 12px var(--accent-yellow-glow);
    }

    .btn-yellow:hover {
      background-color: var(--primary-yellow-hover);
      transform: translateY(-2px);
    }

    .btn-dark {
      background-color: var(--text-dark);
      color: #FFFFFF;
    }

    .btn-dark:hover {
      background-color: #2D3748;
      transform: translateY(-2px);
    }

    .btn-outline {
      background-color: transparent;
      border: 2px solid var(--text-dark);
      color: var(--text-dark);
    }

    .btn-outline:hover {
      background-color: var(--text-dark);
      color: #FFFFFF;
    }

    .mobile-menu-btn {
      display: none;
      background: none;
      border: none;
      font-size: 24px;
      cursor: pointer;
      color: var(--text-dark);
    }

    /* Section Base */
    section {
      padding: 80px 0;
      position: relative;
    }

    .section-header {
      text-align: center;
      max-width: 800px;
      margin: 0 auto 50px auto;
    }

    .section-tag {
      display: inline-block;
      padding: 4px 14px;
      background-color: var(--primary-yellow);
      color: #000;
      font-size: 13px;
      font-weight: 700;
      border-radius: 20px;
      text-transform: uppercase;
      letter-spacing: 1px;
      margin-bottom: 12px;
    }

    .section-title {
      font-size: 32px;
      font-weight: 800;
      color: var(--text-dark);
      margin-bottom: 14px;
      line-height: 1.3;
    }

    .section-subtitle {
      font-size: 16px;
      color: var(--text-muted);
    }

    /* Hero Section - STRICTLY NO IMAGES IN HERO */
    .hero-section {
      background: linear-gradient(180deg, var(--accent-yellow-light) 0%, var(--bg-canvas) 100%);
      padding: 90px 0 70px 0;
      text-align: center;
      border-bottom: 1px solid var(--border-color);
    }

    .hero-badge-group {
      display: flex;
      justify-content: center;
      gap: 10px;
      margin-bottom: 20px;
      flex-wrap: wrap;
    }

    .hero-badge {
      background: #FFFFFF;
      border: 1px solid var(--border-accent);
      padding: 6px 16px;
      border-radius: 20px;
      font-size: 14px;
      font-weight: 600;
      color: var(--text-dark);
      box-shadow: var(--shadow-sm);
    }

    /* Requirement: H1 modified based on main title, length < 20 chars */
    .hero-title {
      font-size: 42px;
      font-weight: 900;
      color: var(--text-dark);
      margin-bottom: 20px;
      letter-spacing: -0.5px;
      line-height: 1.25;
    }

    .hero-description {
      font-size: 18px;
      color: var(--text-muted);
      max-width: 820px;
      margin: 0 auto 36px auto;
      line-height: 1.7;
    }

    .hero-cta-group {
      display: flex;
      justify-content: center;
      align-items: center;
      gap: 16px;
      flex-wrap: wrap;
      margin-bottom: 50px;
    }

    .hero-stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
      margin-top: 40px;
    }

    .stat-card {
      background: var(--bg-card);
      padding: 24px 16px;
      border-radius: var(--radius-md);
      border: 1px solid var(--border-color);
      border-top: 4px solid var(--primary-yellow);
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
    }

    .stat-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }

    .stat-number {
      font-size: 32px;
      font-weight: 900;
      color: var(--text-dark);
      margin-bottom: 4px;
    }

    .stat-label {
      font-size: 14px;
      color: var(--text-muted);
      font-weight: 500;
    }

    /* General Cards Grid */
    .grid-2 {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 24px;
    }

    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }

    .grid-4 {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
    }

    .card {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      padding: 28px;
      transition: var(--transition);
      position: relative;
    }

    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
      border-color: var(--primary-yellow);
    }

    .card-icon {
      width: 48px;
      height: 48px;
      background-color: var(--primary-yellow);
      border-radius: var(--radius-sm);
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 800;
      font-size: 20px;
      margin-bottom: 18px;
      color: #000;
    }

    .card-title {
      font-size: 20px;
      font-weight: 700;
      margin-bottom: 10px;
      color: var(--text-dark);
    }

    .card-text {
      font-size: 14px;
      color: var(--text-muted);
      line-height: 1.6;
    }

    /* Media Image Styling */
    .ai-page-image {
      max-width: 100%;
      height: auto;
      border-radius: var(--radius-md);
      display: block;
      box-shadow: var(--shadow-md);
    }

    .media-block {
      margin: 30px 0;
      display: flex;
      justify-content: center;
      gap: 16px;
      flex-wrap: wrap;
    }

    .media-block img {
      max-width: 100%;
      object-fit: cover;
      border-radius: var(--radius-md);
    }

    /* Matrix Table (Comparison & Models) */
    .table-wrapper {
      width: 100%;
      overflow-x: auto;
      background: #FFFFFF;
      border-radius: var(--radius-md);
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-sm);
    }

    table.data-table {
      width: 100%;
      border-collapse: collapse;
      text-align: left;
    }

    table.data-table th, table.data-table td {
      padding: 16px 20px;
      border-bottom: 1px solid var(--border-color);
      font-size: 14px;
    }

    table.data-table th {
      background-color: var(--accent-yellow-light);
      color: var(--text-dark);
      font-weight: 700;
    }

    table.data-table tr:last-child td {
      border-bottom: none;
    }

    table.data-table tr:hover td {
      background-color: #FFFDE7;
    }

    .highlight-cell {
      background-color: rgba(255, 214, 0, 0.15) !important;
      font-weight: 700;
      color: #000;
    }

    /* Rating Display */
    .rating-badge {
      display: inline-flex;
      align-items: center;
      gap: 10px;
      background: var(--text-dark);
      color: var(--primary-yellow);
      padding: 12px 24px;
      border-radius: 30px;
      font-size: 18px;
      font-weight: 800;
      margin-bottom: 24px;
    }

    /* Process Timeline */
    .timeline {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
      position: relative;
    }

    .step-card {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      padding: 24px;
      border-radius: var(--radius-md);
      position: relative;
    }

    .step-num {
      font-size: 36px;
      font-weight: 900;
      color: var(--primary-yellow);
      line-height: 1;
      margin-bottom: 12px;
    }

    /* Models Cloud Tags */
    .tag-cloud {
      display: flex;
      flex-wrap: wrap;
      gap: 10px;
      justify-content: center;
    }

    .tag-item {
      background: #FFFFFF;
      border: 1px solid var(--border-color);
      padding: 8px 16px;
      border-radius: 20px;
      font-size: 13px;
      font-weight: 600;
      color: var(--text-dark);
      transition: var(--transition);
    }

    .tag-item:hover {
      background-color: var(--primary-yellow);
      border-color: var(--primary-yellow);
      transform: translateY(-2px);
    }

    /* FAQ Accordion */
    .faq-container {
      max-width: 900px;
      margin: 0 auto;
    }

    .faq-item {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      margin-bottom: 12px;
      overflow: hidden;
      transition: var(--transition);
    }

    .faq-question {
      padding: 20px 24px;
      font-weight: 700;
      font-size: 16px;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      user-select: none;
    }

    .faq-question:hover {
      background-color: var(--accent-yellow-light);
    }

    .faq-toggle {
      font-size: 20px;
      font-weight: 800;
      transition: var(--transition);
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease-out;
      background-color: #FFFFFF;
      padding: 0 24px;
      color: var(--text-muted);
      font-size: 14px;
      line-height: 1.7;
    }

    .faq-item.active .faq-answer {
      padding: 0 24px 20px 24px;
      max-height: 300px;
    }

    .faq-item.active .faq-toggle {
      transform: rotate(45deg);
    }

    /* Form Styles */
    .form-box {
      background: #FFFFFF;
      border: 2px solid var(--primary-yellow);
      border-radius: var(--radius-lg);
      padding: 36px;
      box-shadow: var(--shadow-lg);
      max-width: 760px;
      margin: 0 auto;
    }

    .form-group {
      margin-bottom: 20px;
    }

    .form-label {
      display: block;
      font-weight: 600;
      margin-bottom: 8px;
      font-size: 14px;
    }

    .form-input, .form-select, .form-textarea {
      width: 100%;
      padding: 12px 16px;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-sm);
      font-size: 15px;
      transition: var(--transition);
    }

    .form-input:focus, .form-select:focus, .form-textarea:focus {
      outline: none;
      border-color: var(--text-dark);
      box-shadow: 0 0 0 3px var(--accent-yellow-glow);
    }

    .form-textarea {
      resize: vertical;
      min-height: 110px;
    }

    /* Articles & Links */
    .article-list {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 20px;
    }

    .article-card {
      background: #FFFFFF;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      padding: 20px;
      transition: var(--transition);
    }

    .article-card:hover {
      border-color: var(--primary-yellow);
      box-shadow: var(--shadow-sm);
    }

    .friend-links {
      display: flex;
      flex-wrap: wrap;
      gap: 16px;
      justify-content: center;
      margin-top: 20px;
    }

    .friend-links a {
      font-size: 14px;
      color: var(--text-muted);
      background: #FFFFFF;
      padding: 6px 16px;
      border-radius: 20px;
      border: 1px solid var(--border-color);
    }

    .friend-links a:hover {
      color: var(--text-dark);
      border-color: var(--primary-yellow);
      background: var(--primary-yellow);
    }

    /* Footer */
    footer.site-footer {
      background-color: var(--text-dark);
      color: #FFFFFF;
      padding: 60px 0 30px 0;
      border-top: 4px solid var(--primary-yellow);
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 40px;
      margin-bottom: 40px;
    }

    .footer-col h4 {
      font-size: 16px;
      font-weight: 700;
      color: var(--primary-yellow);
      margin-bottom: 20px;
    }

    .footer-col p, .footer-col li {
      font-size: 14px;
      color: #9CA3AF;
      line-height: 1.8;
      list-style: none;
    }

    .footer-qr {
      text-align: center;
    }

    .footer-qr img {
      width: 120px;
      height: 120px;
      border-radius: var(--radius-sm);
      border: 2px solid var(--primary-yellow);
      margin-bottom: 8px;
    }

    .footer-bottom {
      border-top: 1px solid #374151;
      padding-top: 24px;
      text-align: center;
      font-size: 13px;
      color: #9CA3AF;
    }

    /* Floating Customer Service Element */
    .floating-contact {
      position: fixed;
      right: 20px;
      bottom: 30px;
      z-index: 999;
      display: flex;
      flex-direction: column;
      gap: 10px;
    }

    .float-btn {
      width: 50px;
      height: 50px;
      border-radius: 50%;
      background: var(--primary-yellow);
      color: #000;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 800;
      box-shadow: var(--shadow-lg);
      cursor: pointer;
      transition: var(--transition);
      border: none;
    }

    .float-btn:hover {
      transform: scale(1.1);
    }

    /* Responsive Adaptation */
    @media (max-width: 992px) {
      .grid-4, .hero-stats-grid, .timeline {
        grid-template-columns: repeat(2, 1fr);
      }
      .grid-3, .article-list {
        grid-template-columns: repeat(2, 1fr);
      }
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
      .hero-title {
        font-size: 32px;
      }
    }

    @media (max-width: 768px) {
      .nav-links {
        display: none;
        position: absolute;
        top: 72px;
        left: 0;
        width: 100%;
        background: #FFFFFF;
        flex-direction: column;
        padding: 20px;
        box-shadow: var(--shadow-md);
      }
      .nav-links.active {
        display: flex;
      }
      .mobile-menu-btn {
        display: block;
      }
      .grid-2, .grid-3, .grid-4, .article-list, .hero-stats-grid, .timeline {
        grid-template-columns: 1fr;
      }
      .footer-grid {
        grid-template-columns: 1fr;
      }
      .hero-title {
        font-size: 26px;
      }
    }