:root {
      --primary: #4f46e5;
      --primary-light: #6366f1;
      --rainbow-1: #ff5757;
      --rainbow-2: #ff914d;
      --rainbow-3: #ffde59;
      --rainbow-4: #00bf63;
      --rainbow-5: #004aad;
      --rainbow-6: #cb6ce6;
      --text-main: #1f2937;
      --text-muted: #4b5563;
      --text-light: #6b7280;
      --bg-page: #fafbfc;
      --bg-card: #ffffff;
      --border-color: #e5e7eb;
      --border-light: #f3f4f6;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.05);
      --shadow-md: 0 4px 12px rgba(0,0,0,0.06);
      --shadow-lg: 0 10px 25px rgba(0,0,0,0.08);
      --shadow-hover: 0 14px 28px rgba(79, 70, 229, 0.12);
      --radius: 12px;
      --transition: all 0.25s ease;
    }
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }
    body {
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
      background-color: var(--bg-page);
      color: var(--text-main);
      line-height: 1.6;
      overflow-x: hidden;
    }
    .rainbow-line {
      height: 4px;
      width: 100%;
      background: linear-gradient(90deg, var(--rainbow-1), var(--rainbow-2), var(--rainbow-3), var(--rainbow-4), var(--rainbow-5), var(--rainbow-6));
    }
    .container {
      width: 100%;
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 20px;
    }
    .header-bar {
      position: sticky;
      top: 0;
      z-index: 1000;
      background: rgba(255, 255, 255, 0.96);
      backdrop-filter: blur(10px);
      border-bottom: 1px solid var(--border-color);
      box-shadow: var(--shadow-sm);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .brand-wrap {
      display: flex;
      align-items: center;
      gap: 12px;
    }
    .brand-wrap .ai-page-logo {
      height: 38px;
      width: auto;
      display: block;
    }
    .brand-title {
      font-size: 1.25rem;
      font-weight: 700;
      color: #111827;
      letter-spacing: -0.5px;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 0;
      list-style: none;
    }
    .nav-links li a {
      text-decoration: none;
      color: var(--text-muted);
      font-weight: 500;
      font-size: 0.95rem;
      padding: 8px 12px;
      border-radius: 6px;
      transition: var(--transition);
      display: inline-block;
    }
    .nav-links li a:hover {
      color: var(--primary);
      background: #eef2ff;
    }
    .nav-actions {
      display: flex;
      align-items: center;
      gap: 12px;
    }
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 10px 22px;
      font-size: 0.95rem;
      font-weight: 600;
      border-radius: 8px;
      text-decoration: none;
      cursor: pointer;
      transition: var(--transition);
      border: 1px solid transparent;
    }
    .btn-primary {
      background: linear-gradient(135deg, #4f46e5 0%, #7c3aed 100%);
      color: #ffffff;
      box-shadow: 0 4px 10px rgba(79, 70, 229, 0.25);
    }
    .btn-primary:hover {
      opacity: 0.92;
      transform: translateY(-1px);
      box-shadow: 0 6px 16px rgba(79, 70, 229, 0.35);
    }
    .btn-rainbow {
      background: linear-gradient(135deg, #ff5757 0%, #ff914d 50%, #cb6ce6 100%);
      color: #ffffff;
      box-shadow: 0 4px 12px rgba(255, 87, 87, 0.25);
    }
    .btn-rainbow:hover {
      opacity: 0.94;
      transform: translateY(-1px);
      box-shadow: 0 6px 18px rgba(203, 108, 230, 0.35);
    }
    .btn-outline {
      background: #ffffff;
      border-color: #d1d5db;
      color: var(--text-main);
    }
    .btn-outline:hover {
      background: #f9fafb;
      border-color: var(--primary);
      color: var(--primary);
    }
    .menu-toggle {
      display: none;
      background: none;
      border: none;
      font-size: 1.5rem;
      cursor: pointer;
      color: var(--text-main);
      padding: 4px;
    }
    .hero-section {
      padding: 70px 0 60px;
      background: radial-gradient(circle at 10% 20%, rgba(255, 87, 87, 0.05) 0%, rgba(255, 145, 77, 0.04) 25%, rgba(79, 70, 229, 0.05) 50%, rgba(0, 191, 99, 0.04) 75%, #ffffff 100%);
      border-bottom: 1px solid var(--border-color);
      text-align: center;
    }
    .hero-badge {
      display: inline-flex;
      align-items: center;
      gap: 6px;
      padding: 6px 14px;
      background: #f5f3ff;
      border: 1px solid #ddd6fe;
      border-radius: 30px;
      font-size: 0.85rem;
      font-weight: 600;
      color: #6d28d9;
      margin-bottom: 20px;
    }
    .hero-title {
      font-size: 2.75rem;
      font-weight: 800;
      color: #111827;
      letter-spacing: -0.5px;
      line-height: 1.25;
      margin-bottom: 18px;
    }
    .hero-subtitle {
      font-size: 1.15rem;
      color: var(--text-muted);
      max-width: 820px;
      margin: 0 auto 30px;
    }
    .hero-cta {
      display: flex;
      justify-content: center;
      gap: 16px;
      flex-wrap: wrap;
      margin-bottom: 45px;
    }
    .hero-stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 16px;
      margin-top: 30px;
    }
    .stat-card {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      padding: 20px;
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
      border-top: 3px solid transparent;
    }
    .stat-card:nth-child(1) { border-top-color: var(--rainbow-1); }
    .stat-card:nth-child(2) { border-top-color: var(--rainbow-2); }
    .stat-card:nth-child(3) { border-top-color: var(--rainbow-4); }
    .stat-card:nth-child(4) { border-top-color: var(--rainbow-5); }
    .stat-card:hover {
      transform: translateY(-3px);
      box-shadow: var(--shadow-md);
    }
    .stat-num {
      font-size: 1.85rem;
      font-weight: 800;
      color: #111827;
      margin-bottom: 4px;
    }
    .stat-desc {
      font-size: 0.875rem;
      color: var(--text-muted);
    }
    .section-padding {
      padding: 70px 0;
      border-bottom: 1px solid var(--border-light);
    }
    .section-header {
      text-align: center;
      max-width: 720px;
      margin: 0 auto 45px;
    }
    .section-tag {
      display: inline-block;
      font-size: 0.82rem;
      font-weight: 700;
      color: var(--primary);
      text-transform: uppercase;
      letter-spacing: 1px;
      background: #eef2ff;
      padding: 4px 10px;
      border-radius: 4px;
      margin-bottom: 10px;
    }
    .section-title {
      font-size: 2rem;
      font-weight: 700;
      color: #111827;
      margin-bottom: 12px;
    }
    .section-desc {
      font-size: 1rem;
      color: var(--text-muted);
    }
    .grid-2 {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 28px;
    }
    .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-white {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      padding: 24px;
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
      display: flex;
      flex-direction: column;
    }
    .card-white:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
      border-color: #cbd5e1;
    }
    .card-icon {
      width: 44px;
      height: 44px;
      border-radius: 10px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      font-size: 1.1rem;
      margin-bottom: 16px;
      color: #ffffff;
    }
    .card-title {
      font-size: 1.15rem;
      font-weight: 700;
      color: #111827;
      margin-bottom: 10px;
    }
    .card-desc {
      font-size: 0.92rem;
      color: var(--text-muted);
      line-height: 1.6;
      flex-grow: 1;
    }
    .model-tags-bar {
      margin-top: 35px;
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      padding: 24px;
    }
    .model-tags-title {
      font-size: 0.95rem;
      font-weight: 700;
      color: #374151;
      margin-bottom: 14px;
    }
    .tag-cloud {
      display: flex;
      flex-wrap: wrap;
      gap: 8px;
    }
    .tag-item {
      background: #f3f4f6;
      border: 1px solid #e5e7eb;
      color: #374151;
      font-size: 0.85rem;
      padding: 5px 12px;
      border-radius: 6px;
      font-weight: 500;
      transition: var(--transition);
    }
    .tag-item:hover {
      background: #4f46e5;
      color: #ffffff;
      border-color: #4f46e5;
    }
    .step-box {
      text-align: center;
      position: relative;
    }
    .step-num {
      width: 46px;
      height: 46px;
      border-radius: 50%;
      background: linear-gradient(135deg, var(--rainbow-5), var(--rainbow-6));
      color: #ffffff;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      font-size: 1.1rem;
      margin: 0 auto 16px;
      box-shadow: 0 4px 10px rgba(203, 108, 230, 0.3);
    }
    .table-container {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      overflow-x: auto;
      box-shadow: var(--shadow-sm);
    }
    table {
      width: 100%;
      border-collapse: collapse;
      text-align: left;
    }
    th, td {
      padding: 16px 20px;
      border-bottom: 1px solid var(--border-light);
      font-size: 0.93rem;
    }
    th {
      background: #f9fafb;
      font-weight: 700;
      color: #111827;
    }
    tr:last-child td {
      border-bottom: none;
    }
    .rating-badge {
      display: inline-flex;
      align-items: center;
      gap: 4px;
      background: #ecfdf5;
      color: #065f46;
      padding: 4px 10px;
      border-radius: 6px;
      font-weight: 700;
      font-size: 0.88rem;
    }
    .faq-item {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: 8px;
      margin-bottom: 12px;
      overflow: hidden;
      transition: var(--transition);
    }
    .faq-question {
      width: 100%;
      text-align: left;
      padding: 18px 20px;
      background: none;
      border: none;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-size: 1rem;
      font-weight: 600;
      color: #111827;
      cursor: pointer;
    }
    .faq-question:hover {
      color: var(--primary);
    }
    .faq-icon {
      font-size: 1.25rem;
      transition: transform 0.2s ease;
      color: #9ca3af;
    }
    .faq-answer {
      padding: 0 20px;
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s ease;
      font-size: 0.92rem;
      color: var(--text-muted);
      line-height: 1.7;
    }
    .faq-item.active .faq-answer {
      padding: 0 20px 18px;
      max-height: 200px;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
      color: var(--primary);
    }
    .user-comment {
      display: flex;
      flex-direction: column;
      height: 100%;
    }
    .comment-meta {
      display: flex;
      align-items: center;
      gap: 12px;
      margin-top: 18px;
      padding-top: 14px;
      border-top: 1px dashed var(--border-color);
    }
    .avatar-char {
      width: 40px;
      height: 40px;
      border-radius: 50%;
      background: #e0e7ff;
      color: #4338ca;
      font-weight: 700;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 0.95rem;
    }
    .user-info .user-name {
      font-size: 0.92rem;
      font-weight: 700;
      color: #111827;
    }
    .user-info .user-role {
      font-size: 0.8rem;
      color: var(--text-light);
    }
    .form-box {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      padding: 30px;
      box-shadow: var(--shadow-sm);
    }
    .form-group {
      margin-bottom: 18px;
    }
    .form-label {
      display: block;
      font-size: 0.9rem;
      font-weight: 600;
      color: #374151;
      margin-bottom: 6px;
    }
    .form-control {
      width: 100%;
      padding: 10px 14px;
      border: 1px solid #d1d5db;
      border-radius: 6px;
      font-size: 0.95rem;
      color: #111827;
      outline: none;
      transition: var(--transition);
      background: #fdfdfd;
    }
    .form-control:focus {
      border-color: var(--primary);
      box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.15);
      background: #ffffff;
    }
    textarea.form-control {
      resize: vertical;
      min-height: 100px;
    }
    .article-list {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 12px;
    }
    .article-item {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: 8px;
      padding: 16px 20px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      transition: var(--transition);
    }
    .article-item:hover {
      border-color: var(--primary);
      transform: translateX(4px);
    }
    .article-link {
      text-decoration: none;
      color: #1f2937;
      font-weight: 600;
      font-size: 0.95rem;
    }
    .article-link:hover {
      color: var(--primary);
    }
    .article-time {
      font-size: 0.85rem;
      color: var(--text-light);
    }
    .footer-section {
      background: #111827;
      color: #9ca3af;
      padding: 60px 0 30px;
      border-top: 1px solid #1f2937;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 30px;
      margin-bottom: 40px;
    }
    .footer-col h4 {
      color: #ffffff;
      font-size: 1.05rem;
      font-weight: 700;
      margin-bottom: 16px;
    }
    .footer-links {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 10px;
    }
    .footer-links a {
      color: #9ca3af;
      text-decoration: none;
      font-size: 0.9rem;
      transition: var(--transition);
    }
    .footer-links a:hover {
      color: #ffffff;
    }
    .footer-contact-item {
      margin-bottom: 8px;
      font-size: 0.9rem;
    }
    .footer-contact-item strong {
      color: #d1d5db;
    }
    .friend-links {
      display: flex;
      flex-wrap: wrap;
      gap: 12px;
      margin-top: 12px;
    }
    .friend-links a {
      color: #9ca3af;
      text-decoration: none;
      font-size: 0.85rem;
      background: #1f2937;
      padding: 4px 10px;
      border-radius: 4px;
      transition: var(--transition);
    }
    .friend-links a:hover {
      color: #ffffff;
      background: #374151;
    }
    .footer-bottom {
      border-top: 1px solid #1f2937;
      padding-top: 24px;
      text-align: center;
      font-size: 0.85rem;
      color: #6b7280;
    }
    .float-panel {
      position: fixed;
      right: 20px;
      bottom: 40px;
      display: flex;
      flex-direction: column;
      gap: 10px;
      z-index: 999;
    }
    .float-btn {
      width: 44px;
      height: 44px;
      border-radius: 50%;
      background: #ffffff;
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-md);
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--primary);
      cursor: pointer;
      text-decoration: none;
      transition: var(--transition);
      font-weight: 700;
      font-size: 0.9rem;
    }
    .float-btn:hover {
      background: var(--primary);
      color: #ffffff;
      transform: scale(1.05);
    }
    .img-box {
      width: 100%;
      border-radius: var(--radius);
      overflow: hidden;
      border: 1px solid var(--border-color);
      background: #ffffff;
      margin-bottom: 12px;
    }
    .img-box img {
      width: 100%;
      height: auto;
      display: block;
      transition: var(--transition);
    }
    .img-box:hover img {
      transform: scale(1.02);
    }
    @media (max-width: 992px) {
      .grid-4 { grid-template-columns: repeat(2, 1fr); }
      .grid-3 { grid-template-columns: repeat(2, 1fr); }
      .hero-stats-grid { grid-template-columns: repeat(2, 1fr); }
      .footer-grid { grid-template-columns: repeat(2, 1fr); }
      .nav-links { display: none; }
      .nav-links.active {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 72px;
        left: 0;
        width: 100%;
        background: #ffffff;
        border-bottom: 1px solid var(--border-color);
        padding: 16px 20px;
        gap: 8px;
        box-shadow: var(--shadow-md);
      }
      .menu-toggle { display: block; }
    }
    @media (max-width: 640px) {
      .grid-4, .grid-3, .grid-2 { grid-template-columns: 1fr; }
      .hero-stats-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr; }
      .hero-title { font-size: 2rem; }
      .hero-cta { flex-direction: column; }
      .hero-cta .btn { width: 100%; }
    }