:root {
      --primary: #6366f1;
      --primary-dark: #4f46e5;
      --secondary: #ec4899;
      --accent: #f59e0b;
      --emerald: #10b981;
      --cyan: #06b6d4;
      --bg-light: #ffffff;
      --bg-alt: #f8fafc;
      --bg-subtle: #f1f5f9;
      --text-main: #0f172a;
      --text-muted: #334155;
      --text-soft: #64748b;
      --border-color: rgba(99, 102, 241, 0.15);
      --rainbow-grad: linear-gradient(135deg, #6366f1 0%, #a855f7 35%, #ec4899 70%, #f59e0b 100%);
      --rainbow-bar: linear-gradient(90deg, #6366f1, #3b82f6, #10b981, #f59e0b, #ec4899);
      --shadow-sm: 0 4px 6px -1px rgba(0,0,0,0.05);
      --shadow-md: 0 10px 25px -5px rgba(99,102,241,0.1);
      --shadow-lg: 0 20px 30px -10px rgba(99,102,241,0.15);
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-lg: 20px;
    }

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

    body {
      overflow-x: hidden;
      background: var(--bg-light);
    }

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

    /* 顶部彩虹装饰条 */
    .top-rainbow-line {
      height: 4px;
      background: var(--rainbow-bar);
      width: 100%;
    }

    /* Header & Navigation */
    header.site-header {
      position: sticky;
      top: 0;
      z-index: 1000;
      background: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid rgba(226, 232, 240, 0.8);
      box-shadow: var(--shadow-sm);
    }

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

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

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

    .brand-title {
      font-size: 1.25rem;
      font-weight: 800;
      background: var(--rainbow-grad);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }

    nav.main-nav {
      display: flex;
      align-items: center;
    }

    .nav-links {
      gap: 0;
      display: flex;
      align-items: center;
      list-style: none;
      margin: 0;
      padding: 0;
    }

    .nav-links li {
      display: inline-block;
    }

    .nav-links a {
      display: block;
      padding: 8px 12px;
      font-size: 0.9rem;
      font-weight: 500;
      color: var(--text-muted);
      text-decoration: none;
      transition: all 0.2s ease;
      white-space: nowrap;
    }

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

    .header-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: 99px;
      text-decoration: none;
      transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
      cursor: pointer;
      border: none;
    }

    .btn-rainbow {
      background: var(--rainbow-grad);
      color: #ffffff !important;
      box-shadow: 0 4px 15px rgba(99, 102, 241, 0.35);
    }

    .btn-rainbow:hover {
      transform: translateY(-2px);
      box-shadow: 0 8px 25px rgba(236, 72, 153, 0.45);
    }

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

    .btn-outline:hover {
      background: rgba(99, 102, 241, 0.08);
      transform: translateY(-2px);
    }

    .btn-subtle {
      background: var(--bg-subtle);
      color: var(--text-main);
    }

    .btn-subtle:hover {
      background: #e2e8f0;
    }

    .mobile-menu-toggle {
      display: none;
      background: none;
      border: none;
      font-size: 1.5rem;
      color: var(--text-main);
      cursor: pointer;
    }

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

    .section-bg-alt {
      background-color: var(--bg-alt);
      border-top: 1px solid #f1f5f9;
      border-bottom: 1px solid #f1f5f9;
    }

    .section-header {
      text-align: center;
      max-width: 760px;
      margin: 0 auto 50px auto;
    }

    .section-badge {
      display: inline-block;
      padding: 4px 16px;
      border-radius: 99px;
      font-size: 0.85rem;
      font-weight: 700;
      letter-spacing: 1px;
      text-transform: uppercase;
      background: rgba(99, 102, 241, 0.1);
      color: var(--primary);
      margin-bottom: 12px;
      border: 1px solid rgba(99, 102, 241, 0.2);
    }

    .section-title {
      font-size: 2.2rem;
      font-weight: 800;
      color: var(--text-main);
      margin-bottom: 16px;
      line-height: 1.3;
    }

    .section-subtitle {
      font-size: 1.05rem;
      color: var(--text-soft);
    }

    /* Hero Section (No Images Allowed) */
    #hero {
      padding: 90px 0 80px 0;
      background: radial-gradient(circle at 50% 0%, rgba(99, 102, 241, 0.12) 0%, rgba(236, 72, 153, 0.05) 50%, rgba(255, 255, 255, 0) 100%);
      text-align: center;
    }

    .hero-content {
      max-width: 920px;
      margin: 0 auto;
    }

    .hero-tag {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      padding: 6px 20px;
      border-radius: 99px;
      background: #ffffff;
      box-shadow: 0 4px 20px rgba(99, 102, 241, 0.12);
      border: 1px solid rgba(99, 102, 241, 0.2);
      font-size: 0.9rem;
      font-weight: 600;
      color: var(--primary);
      margin-bottom: 24px;
    }

    .hero-title {
      font-size: 2.8rem;
      font-weight: 900;
      letter-spacing: -0.5px;
      line-height: 1.2;
      margin-bottom: 24px;
      background: linear-gradient(135deg, #0f172a 0%, #4338ca 50%, #6366f1 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }

    .hero-desc {
      font-size: 1.2rem;
      color: var(--text-muted);
      max-width: 780px;
      margin: 0 auto 36px auto;
      line-height: 1.7;
    }

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

    .hero-tags-cloud {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      gap: 10px;
      max-width: 850px;
      margin: 0 auto 40px auto;
    }

    .hero-tag-item {
      padding: 6px 14px;
      background: rgba(255, 255, 255, 0.9);
      border: 1px solid var(--border-color);
      border-radius: 8px;
      font-size: 0.85rem;
      font-weight: 600;
      color: var(--text-muted);
      box-shadow: var(--shadow-sm);
    }

    .hero-stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
      background: #ffffff;
      padding: 30px;
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-md);
      border: 1px solid rgba(99, 102, 241, 0.12);
    }

    .stat-item {
      text-align: center;
    }

    .stat-number {
      font-size: 2.2rem;
      font-weight: 800;
      background: var(--rainbow-grad);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }

    .stat-label {
      font-size: 0.9rem;
      color: var(--text-soft);
      font-weight: 500;
      margin-top: 4px;
    }

    /* Cards & Grids */
    .grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 30px; }
    .grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px; }
    .grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }

    .card {
      background: #ffffff;
      border-radius: var(--radius-md);
      padding: 28px;
      border: 1px solid rgba(226, 232, 240, 0.8);
      box-shadow: var(--shadow-sm);
      transition: all 0.3s ease;
      position: relative;
      overflow: hidden;
    }

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

    .card::before {
      content: "";
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 3px;
      background: var(--rainbow-bar);
      opacity: 0;
      transition: opacity 0.3s ease;
    }

    .card:hover::before {
      opacity: 1;
    }

    .card-icon {
      width: 50px;
      height: 50px;
      border-radius: 12px;
      background: rgba(99, 102, 241, 0.1);
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 1.5rem;
      color: var(--primary);
      margin-bottom: 20px;
    }

    .card-title {
      font-size: 1.2rem;
      font-weight: 700;
      margin-bottom: 10px;
      color: var(--text-main);
    }

    .card-desc {
      font-size: 0.95rem;
      color: var(--text-soft);
      line-height: 1.6;
    }

    /* Model Pill Wall */
    .models-wall {
      display: flex;
      flex-wrap: wrap;
      gap: 12px;
      justify-content: center;
    }

    .model-chip {
      padding: 8px 18px;
      border-radius: 99px;
      background: #ffffff;
      border: 1px solid #e2e8f0;
      font-size: 0.9rem;
      font-weight: 600;
      color: var(--text-muted);
      box-shadow: var(--shadow-sm);
      transition: all 0.2s ease;
    }

    .model-chip:hover {
      border-color: var(--primary);
      color: var(--primary);
      transform: scale(1.05);
    }

    /* Comparison Table */
    .comparison-wrapper {
      background: #ffffff;
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-md);
      overflow: hidden;
      border: 1px solid #e2e8f0;
    }

    .score-banner {
      background: var(--rainbow-grad);
      color: #ffffff;
      padding: 24px 30px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      flex-wrap: wrap;
      gap: 16px;
    }

    .score-banner-title {
      font-size: 1.3rem;
      font-weight: 800;
    }

    .score-badge-group {
      display: flex;
      align-items: center;
      gap: 20px;
    }

    .score-item-tag {
      background: rgba(255, 255, 255, 0.2);
      backdrop-filter: blur(5px);
      padding: 6px 16px;
      border-radius: 99px;
      font-weight: 700;
      font-size: 1rem;
    }

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

    .comparison-table th, .comparison-table td {
      padding: 18px 24px;
      border-bottom: 1px solid #e2e8f0;
    }

    .comparison-table th {
      background: #f8fafc;
      font-weight: 700;
      color: var(--text-main);
    }

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

    .highlight-col {
      background: rgba(99, 102, 241, 0.03);
      font-weight: 600;
      color: var(--primary);
    }

    /* Media Showcase Card */
    .case-card {
      background: #ffffff;
      border-radius: var(--radius-md);
      overflow: hidden;
      border: 1px solid #e2e8f0;
      box-shadow: var(--shadow-sm);
    }

    .case-img-wrap {
      width: 100%;
      height: 220px;
      overflow: hidden;
      background: #f1f5f9;
    }

    .case-img-wrap img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      transition: transform 0.4s ease;
    }

    .case-card:hover .case-img-wrap img {
      transform: scale(1.05);
    }

    .case-info {
      padding: 20px;
    }

    /* FAQ Accordion */
    .faq-list {
      max-width: 900px;
      margin: 0 auto;
      display: flex;
      flex-direction: column;
      gap: 16px;
    }

    .faq-item {
      background: #ffffff;
      border-radius: var(--radius-md);
      border: 1px solid #e2e8f0;
      overflow: hidden;
      box-shadow: var(--shadow-sm);
    }

    .faq-question {
      padding: 20px 24px;
      font-size: 1.05rem;
      font-weight: 700;
      color: var(--text-main);
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: space-between;
      user-select: none;
    }

    .faq-question::after {
      content: "+";
      font-size: 1.4rem;
      color: var(--primary);
      transition: transform 0.3s ease;
    }

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

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s cubic-bezier(0, 1, 0, 1);
      background: #f8fafc;
    }

    .faq-answer-inner {
      padding: 20px 24px;
      color: var(--text-muted);
      font-size: 0.95rem;
      line-height: 1.7;
      border-top: 1px solid #e2e8f0;
    }

    .faq-item.active .faq-answer {
      max-height: 500px;
      transition: max-height 0.3s ease-in-out;
    }

    /* Testimonials */
    .testimonial-card {
      background: #ffffff;
      padding: 24px;
      border-radius: var(--radius-md);
      border: 1px solid #e2e8f0;
      box-shadow: var(--shadow-sm);
    }

    .testimonial-header {
      display: flex;
      align-items: center;
      gap: 14px;
      margin-bottom: 16px;
    }

    .avatar-placeholder {
      width: 48px;
      height: 48px;
      border-radius: 50%;
      background: var(--rainbow-grad);
      color: #ffffff;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      font-size: 1.1rem;
    }

    .user-info h4 {
      font-size: 1rem;
      font-weight: 700;
      color: var(--text-main);
    }

    .user-info p {
      font-size: 0.85rem;
      color: var(--text-soft);
    }

    .rating-stars {
      color: var(--accent);
      font-size: 0.9rem;
      margin-bottom: 10px;
    }

    /* Form Styles */
    .form-container {
      background: #ffffff;
      padding: 40px;
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-md);
      border: 1px solid #e2e8f0;
      max-width: 800px;
      margin: 0 auto;
    }

    .form-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 20px;
    }

    .form-group {
      display: flex;
      flex-direction: column;
      gap: 8px;
    }

    .form-group.full-width {
      grid-column: span 2;
    }

    .form-label {
      font-size: 0.9rem;
      font-weight: 600;
      color: var(--text-main);
    }

    .form-input, .form-select, .form-textarea {
      padding: 12px 16px;
      border: 1px solid #cbd5e1;
      border-radius: 8px;
      font-size: 0.95rem;
      outline: none;
      transition: border-color 0.2s ease;
      background: #ffffff;
      color: var(--text-main);
    }

    .form-input:focus, .form-select:focus, .form-textarea:focus {
      border-color: var(--primary);
      box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
    }

    /* Article Links Grid */
    .articles-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 16px;
    }

    .article-item-link {
      display: block;
      padding: 16px 20px;
      background: #ffffff;
      border-radius: var(--radius-sm);
      border: 1px solid #e2e8f0;
      color: var(--text-main);
      text-decoration: none;
      font-weight: 600;
      transition: all 0.2s ease;
    }

    .article-item-link:hover {
      border-color: var(--primary);
      color: var(--primary);
      transform: translateX(4px);
    }

    /* Footer */
    footer.site-footer {
      background: #0f172a;
      color: #94a3b8;
      padding: 70px 0 30px 0;
      border-top: 4px solid var(--primary);
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 40px;
      margin-bottom: 50px;
    }

    .footer-col h3 {
      color: #ffffff;
      font-size: 1.1rem;
      font-weight: 700;
      margin-bottom: 20px;
    }

    .footer-col p, .footer-col li {
      font-size: 0.9rem;
      line-height: 1.8;
    }

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

    .footer-links-list a {
      color: #94a3b8;
      text-decoration: none;
      transition: color 0.2s ease;
    }

    .footer-links-list a:hover {
      color: #ffffff;
    }

    .friendship-links {
      display: flex;
      flex-wrap: wrap;
      gap: 12px;
      margin-top: 10px;
    }

    .friendship-links a {
      color: #cbd5e1;
      background: rgba(255, 255, 255, 0.08);
      padding: 4px 12px;
      border-radius: 6px;
      font-size: 0.85rem;
      text-decoration: none;
      transition: background 0.2s ease;
    }

    .friendship-links a:hover {
      background: rgba(255, 255, 255, 0.2);
      color: #ffffff;
    }

    .footer-bottom {
      border-top: 1px solid rgba(255, 255, 255, 0.1);
      padding-top: 30px;
      text-align: center;
      font-size: 0.85rem;
      color: #64748b;
    }

    /* Floating Contact */
    .floating-kefu {
      position: fixed;
      bottom: 30px;
      right: 30px;
      z-index: 999;
      background: #ffffff;
      padding: 12px;
      border-radius: 16px;
      box-shadow: var(--shadow-lg);
      border: 1px solid var(--border-color);
      text-align: center;
      width: 130px;
    }

    .floating-kefu img {
      width: 100px;
      height: 100px;
      border-radius: 8px;
    }

    .floating-kefu p {
      font-size: 0.75rem;
      font-weight: 700;
      color: var(--text-main);
      margin-top: 6px;
    }

    /* Responsive Design */
    @media (max-width: 1024px) {
      .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: 1fr 1fr; }
    }

    @media (max-width: 768px) {
      .nav-links { display: none; }
      .mobile-menu-toggle { display: block; }
      .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
      .hero-title { font-size: 2rem; }
      .hero-stats-grid { grid-template-columns: 1fr 1fr; }
      .form-grid { grid-template-columns: 1fr; }
      .form-group.full-width { grid-column: span 1; }
      .footer-grid { grid-template-columns: 1fr; }
      .floating-kefu { display: none; }
      .articles-grid { grid-template-columns: 1fr; }
    }