/* CSS Variables & Global Reset - Vibrant Trend Light Style */
    :root {
      --primary: #6366f1;
      --primary-hover: #4f46e5;
      --secondary: #ec4899;
      --accent: #06b6d4;
      --bg-body: #f8fafc;
      --bg-surface: #ffffff;
      --bg-alt: #f1f5f9;
      --text-main: #0f172a;
      --text-muted: #475569;
      --border-color: #e2e8f0;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.05);
      --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
      --shadow-lg: 0 12px 24px -4px rgba(99,102,241,0.15);
      --radius: 12px;
      --container-max: 1200px;
    }

    * {
      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-body);
      color: var(--text-main);
      line-height: 1.6;
    }

    body {
      overflow-x: hidden;
    }

    a {
      color: var(--primary);
      text-decoration: none;
      transition: all 0.2s ease;
    }
    a:hover {
      color: var(--primary-hover);
    }

    .container {
      width: 100%;
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 20px;
    }

    /* Section Global Styles */
    section {
      padding: 70px 0;
      position: relative;
    }

    .section-header {
      text-align: center;
      margin-bottom: 45px;
    }

    .section-badge {
      display: inline-block;
      padding: 5px 14px;
      background: linear-gradient(135deg, rgba(99,102,241,0.1), rgba(236,72,153,0.1));
      color: var(--primary);
      font-size: 13px;
      font-weight: 700;
      border-radius: 20px;
      text-transform: uppercase;
      letter-spacing: 1px;
      margin-bottom: 10px;
      border: 1px solid rgba(99,102,241,0.2);
    }

    .section-title {
      font-size: 32px;
      font-weight: 800;
      color: var(--text-main);
      margin-bottom: 12px;
      letter-spacing: -0.5px;
    }

    .section-desc {
      font-size: 16px;
      color: var(--text-muted);
      max-width: 700px;
      margin: 0 auto;
    }

    /* Header & Navigation */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 1000;
      background: rgba(255, 255, 255, 0.92);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border-color);
    }

    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 70px;
    }

    .logo-box {
      display: flex;
      align-items: center;
      gap: 10px;
    }

    .ai-page-logo {
      height: 40px;
      width: auto;
      object-fit: contain;
    }

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

    .nav-links li a {
      display: block;
      padding: 8px 14px;
      font-size: 14px;
      font-weight: 600;
      color: var(--text-main);
      border-radius: 6px;
    }

    .nav-links li a:hover {
      color: var(--primary);
      background-color: rgba(99,102,241,0.06);
    }

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

    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 10px 22px;
      font-size: 14px;
      font-weight: 700;
      border-radius: 8px;
      cursor: pointer;
      border: none;
      transition: all 0.25s ease;
      text-decoration: none;
    }

    .btn-primary {
      background: linear-gradient(135deg, var(--primary), var(--secondary));
      color: #ffffff !important;
      box-shadow: 0 4px 14px rgba(99,102,241,0.35);
    }

    .btn-primary:hover {
      transform: translateY(-2px);
      box-shadow: 0 6px 20px rgba(99,102,241,0.45);
    }

    .btn-secondary {
      background-color: #ffffff;
      color: var(--text-main);
      border: 1px solid var(--border-color);
    }

    .btn-secondary:hover {
      background-color: var(--bg-alt);
      border-color: #cbd5e1;
    }

    /* Hero Section (No images strictly allowed) */
    .hero-section {
      background: radial-gradient(circle at 50% 0%, rgba(99,102,241,0.12) 0%, rgba(236,72,153,0.05) 50%, rgba(248,250,252,0) 100%), var(--bg-body);
      padding: 90px 0 60px;
      text-align: center;
    }

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

    .hero-badge {
      background: #ffffff;
      padding: 6px 16px;
      border-radius: 30px;
      font-size: 13px;
      font-weight: 700;
      color: var(--primary);
      box-shadow: var(--shadow-sm);
      border: 1px solid rgba(99,102,241,0.2);
    }

    .hero-title {
      font-size: 42px;
      font-weight: 900;
      line-height: 1.25;
      margin-bottom: 20px;
      color: var(--text-main);
      background: linear-gradient(135deg, #0f172a 0%, #334155 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }

    .hero-subtitle {
      font-size: 18px;
      color: var(--text-muted);
      max-width: 800px;
      margin: 0 auto 35px;
    }

    .hero-buttons {
      display: flex;
      justify-content: center;
      gap: 16px;
      margin-bottom: 50px;
      flex-wrap: wrap;
    }

    .hero-stats {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
      gap: 20px;
      background: #ffffff;
      padding: 30px;
      border-radius: 16px;
      box-shadow: var(--shadow-md);
      border: 1px solid var(--border-color);
    }

    .stat-item h3 {
      font-size: 32px;
      font-weight: 800;
      color: var(--primary);
      margin-bottom: 4px;
    }

    .stat-item p {
      font-size: 14px;
      color: var(--text-muted);
    }

    /* Models Aggregation Tag Cloud */
    .models-cloud {
      background-color: var(--bg-surface);
      border-top: 1px solid var(--border-color);
      border-bottom: 1px solid var(--border-color);
      padding: 35px 0;
    }

    .models-list {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      gap: 10px;
      margin-top: 15px;
    }

    .model-tag {
      background: var(--bg-alt);
      padding: 6px 14px;
      border-radius: 6px;
      font-size: 13px;
      font-weight: 600;
      color: var(--text-main);
      border: 1px solid var(--border-color);
      transition: all 0.2s ease;
    }

    .model-tag:hover {
      background: var(--primary);
      color: #ffffff;
      border-color: var(--primary);
    }

    /* Grid Layouts */
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
      gap: 24px;
    }

    .grid-4 {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
      gap: 20px;
    }

    .grid-2 {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(450px, 1fr));
      gap: 30px;
    }

    /* Cards */
    .card {
      background: var(--bg-surface);
      border-radius: var(--radius);
      padding: 28px;
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-sm);
      transition: all 0.3s ease;
    }

    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-lg);
      border-color: rgba(99,102,241,0.3);
    }

    .card-icon {
      width: 48px;
      height: 48px;
      background: linear-gradient(135deg, rgba(99,102,241,0.1), rgba(6,182,212,0.1));
      color: var(--primary);
      border-radius: 10px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 22px;
      font-weight: bold;
      margin-bottom: 18px;
    }

    .card h3 {
      font-size: 18px;
      font-weight: 700;
      margin-bottom: 10px;
      color: var(--text-main);
    }

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

    /* Image Display Wrapper */
    .img-box {
      border-radius: var(--radius);
      overflow: hidden;
      margin-top: 15px;
      border: 1px solid var(--border-color);
      background-color: var(--bg-alt);
    }

    .ai-page-image {
      width: 100%;
      height: auto;
      display: block;
      transition: transform 0.3s ease;
    }

    .img-box:hover .ai-page-image {
      transform: scale(1.02);
    }

    /* Table Styling */
    .table-wrapper {
      width: 100%;
      overflow-x: auto;
      background: var(--bg-surface);
      border-radius: var(--radius);
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-sm);
    }

    table {
      width: 100%;
      border-collapse: collapse;
      text-align: left;
      font-size: 14px;
    }

    th, td {
      padding: 16px 20px;
      border-bottom: 1px solid var(--border-color);
    }

    th {
      background-color: var(--bg-alt);
      font-weight: 700;
      color: var(--text-main);
    }

    tr:hover td {
      background-color: rgba(99,102,241,0.02);
    }

    .badge-star {
      background: #fef3c7;
      color: #d97706;
      padding: 4px 10px;
      border-radius: 4px;
      font-weight: 700;
    }

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

    .faq-item {
      background: var(--bg-surface);
      border: 1px solid var(--border-color);
      border-radius: 10px;
      margin-bottom: 12px;
      overflow: hidden;
    }

    .faq-question {
      padding: 18px 24px;
      font-weight: 700;
      font-size: 16px;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      background-color: var(--bg-surface);
      user-select: none;
    }

    .faq-question:after {
      content: '+';
      font-size: 20px;
      color: var(--primary);
      font-weight: bold;
    }

    .faq-item.active .faq-question:after {
      content: '−';
    }

    .faq-answer {
      padding: 0 24px 18px;
      color: var(--text-muted);
      font-size: 14px;
      display: none;
    }

    .faq-item.active .faq-answer {
      display: block;
    }

    /* Form Design */
    .form-container {
      background: var(--bg-surface);
      padding: 35px;
      border-radius: var(--radius);
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-md);
      max-width: 800px;
      margin: 0 auto;
    }

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

    .form-group label {
      display: block;
      font-size: 14px;
      font-weight: 700;
      margin-bottom: 8px;
    }

    .form-control {
      width: 100%;
      padding: 12px 16px;
      font-size: 14px;
      border: 1px solid var(--border-color);
      border-radius: 8px;
      background-color: var(--bg-body);
      color: var(--text-main);
      outline: none;
      transition: border-color 0.2s;
    }

    .form-control:focus {
      border-color: var(--primary);
      background-color: #ffffff;
    }

    textarea.form-control {
      min-height: 120px;
      resize: vertical;
    }

    /* Footer */
    footer {
      background-color: #ffffff;
      border-top: 1px solid var(--border-color);
      padding: 50px 0 25px;
      color: var(--text-muted);
      font-size: 14px;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
      gap: 30px;
      margin-bottom: 40px;
    }

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

    .footer-links {
      list-style: none;
    }

    .footer-links li {
      margin-bottom: 8px;
    }

    .footer-links a {
      color: var(--text-muted);
    }

    .footer-links a:hover {
      color: var(--primary);
    }

    .friend-links {
      display: flex;
      flex-wrap: wrap;
      gap: 12px;
      margin-top: 15px;
    }

    .friend-links a {
      background: var(--bg-alt);
      padding: 4px 10px;
      border-radius: 4px;
      font-size: 12px;
      color: var(--text-muted);
    }

    .footer-bottom {
      text-align: center;
      padding-top: 25px;
      border-top: 1px solid var(--border-color);
      font-size: 13px;
    }

    /* Floating Customer Service */
    .floating-kefu {
      position: fixed;
      right: 20px;
      bottom: 30px;
      z-index: 999;
      background: #ffffff;
      padding: 12px;
      border-radius: 12px;
      box-shadow: var(--shadow-lg);
      border: 1px solid var(--border-color);
      text-align: center;
      width: 140px;
    }

    .floating-kefu img {
      width: 100px;
      height: 100px;
      border-radius: 6px;
      object-fit: cover;
      margin-bottom: 6px;
    }

    .floating-kefu p {
      font-size: 12px;
      font-weight: 700;
      color: var(--text-main);
    }

    /* Mobile Responsive */
    @media (max-width: 768px) {
      .nav-links {
        display: none; /* Can toggle via JS */
        position: absolute;
        top: 70px;
        left: 0;
        width: 100%;
        background: #ffffff;
        flex-direction: column;
        padding: 15px 0;
        border-bottom: 1px solid var(--border-color);
        box-shadow: var(--shadow-md);
      }
      .nav-links.active {
        display: flex;
      }
      .hero-title {
        font-size: 28px;
      }
      .section-title {
        font-size: 24px;
      }
      .grid-2, .grid-3, .grid-4 {
        grid-template-columns: 1fr;
      }
      .floating-kefu {
        display: none; /* Hide on small screens to reduce clutter */
      }
      .menu-toggle {
        display: block;
        font-size: 24px;
        cursor: pointer;
        background: none;
        border: none;
        color: var(--text-main);
      }
    }

    @media (min-width: 769px) {
      .menu-toggle {
        display: none;
      }
    }