/* CSS RESET & VARIABLES - Vibrant Orange Theme (亮橙炽艳风) */
    :root {
      --primary-color: #FF5500;
      --primary-hover: #E04B00;
      --primary-light: #FFF4EE;
      --primary-border: #FFD4C2;
      --accent-gold: #FF9900;
      --bg-main: #F8F9FC;
      --bg-white: #FFFFFF;
      --bg-dark: #16181D;
      --text-main: #1E2025;
      --text-muted: #5A606D;
      --text-light: #8C95A6;
      --border-color: #E6E8F0;
      --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
      --shadow-md: 0 8px 24px rgba(255, 85, 0, 0.08);
      --shadow-hover: 0 14px 36px rgba(255, 85, 0, 0.15);
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-lg: 16px;
      --transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    }

    * {
      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-main);
      color: var(--text-main);
      line-height: 1.6;
      overflow-x: hidden;
    }

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

    img {
      max-width: 100%;
      height: auto;
      display: block;
    }

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

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

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

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

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

    /* MANDATORY CONSTRAINT: .nav-links gap must be 0 */
    .nav-links {
      display: flex;
      align-items: center;
      gap: 0;
      list-style: none;
    }

    .nav-links li a {
      display: inline-block;
      padding: 8px 14px;
      font-size: 0.92rem;
      font-weight: 500;
      color: var(--text-main);
      border-radius: var(--radius-sm);
    }

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

    .ai-page-home-link {
      font-weight: 700 !important;
      color: var(--primary-color) !important;
    }

    .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: var(--radius-sm);
      cursor: pointer;
      border: 1px solid transparent;
      transition: var(--transition);
      white-space: nowrap;
    }

    .btn-primary {
      background: linear-gradient(135deg, #FF6B00 0%, #FF3300 100%);
      color: #FFFFFF;
      box-shadow: 0 4px 14px rgba(255, 85, 0, 0.3);
    }

    .btn-primary:hover {
      background: linear-gradient(135deg, #FF5500 0%, #E02E00 100%);
      transform: translateY(-2px);
      box-shadow: 0 6px 20px rgba(255, 85, 0, 0.4);
    }

    .btn-outline {
      border-color: var(--primary-color);
      color: var(--primary-color);
      background: var(--bg-white);
    }

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

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

    /* Hero Section (MUST BE IMAGE-FREE) */
    .hero-section {
      background: radial-gradient(circle at 70% 20%, rgba(255, 85, 0, 0.08) 0%, rgba(255, 255, 255, 0) 60%),
                  linear-gradient(180deg, #FFFFFF 0%, #F8F9FC 100%);
      padding: 70px 0 60px 0;
      text-align: center;
      position: relative;
      border-bottom: 1px solid var(--border-color);
    }

    .hero-badge {
      display: inline-flex;
      align-items: center;
      padding: 6px 16px;
      background: var(--primary-light);
      border: 1px solid var(--primary-border);
      color: var(--primary-color);
      border-radius: 50px;
      font-size: 0.88rem;
      font-weight: 600;
      margin-bottom: 24px;
    }

    .hero-h1 {
      font-size: 2.5rem;
      font-weight: 800;
      color: var(--text-main);
      line-height: 1.25;
      margin-bottom: 20px;
      letter-spacing: -0.5px;
    }

    .hero-h1 span {
      background: linear-gradient(135deg, #FF6B00 0%, #D92B00 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }

    .hero-desc {
      font-size: 1.15rem;
      color: var(--text-muted);
      max-width: 840px;
      margin: 0 auto 36px auto;
    }

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

    .hero-stats {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
      max-width: 1000px;
      margin: 0 auto;
    }

    .stat-card {
      background: var(--bg-white);
      border: 1px solid var(--border-color);
      padding: 22px 16px;
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
    }

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

    .stat-num {
      font-size: 2rem;
      font-weight: 800;
      color: var(--primary-color);
      line-height: 1.1;
      margin-bottom: 4px;
    }

    .stat-label {
      font-size: 0.88rem;
      color: var(--text-muted);
    }

    /* Section Base Layout */
    .section-block {
      padding: 80px 0;
      border-bottom: 1px solid var(--border-color);
    }

    .section-white {
      background: var(--bg-white);
    }

    .section-header {
      text-align: center;
      max-width: 720px;
      margin: 0 auto 50px auto;
    }

    .section-tag {
      font-size: 0.85rem;
      font-weight: 700;
      color: var(--primary-color);
      text-transform: uppercase;
      letter-spacing: 1px;
      margin-bottom: 8px;
      display: block;
    }

    .section-title {
      font-size: 2rem;
      font-weight: 800;
      color: var(--text-main);
      margin-bottom: 14px;
    }

    .section-subtitle {
      font-size: 1rem;
      color: var(--text-muted);
    }

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

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

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

    .feature-card {
      background: var(--bg-white);
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      padding: 30px;
      transition: var(--transition);
      display: flex;
      flex-direction: column;
    }

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

    .card-icon {
      width: 52px;
      height: 52px;
      border-radius: var(--radius-sm);
      background: var(--primary-light);
      color: var(--primary-color);
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 1.5rem;
      margin-bottom: 20px;
      font-weight: 700;
    }

    .card-title {
      font-size: 1.25rem;
      font-weight: 700;
      margin-bottom: 12px;
      color: var(--text-main);
    }

    .card-desc {
      font-size: 0.95rem;
      color: var(--text-muted);
      margin-bottom: 20px;
      flex-grow: 1;
    }

    .card-tags {
      display: flex;
      flex-wrap: wrap;
      gap: 6px;
    }

    .tag {
      background: #F1F3F9;
      color: var(--text-muted);
      font-size: 0.78rem;
      padding: 3px 10px;
      border-radius: 4px;
    }

    /* Model Cloud Tag Wall */
    .model-tags-container {
      display: flex;
      flex-wrap: wrap;
      gap: 10px;
      justify-content: center;
      margin-top: 30px;
    }

    .model-badge {
      background: var(--bg-white);
      border: 1px solid var(--border-color);
      padding: 8px 16px;
      border-radius: 30px;
      font-size: 0.9rem;
      font-weight: 600;
      color: var(--text-main);
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
    }

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

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

    .step-item {
      background: var(--bg-white);
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      padding: 28px 20px;
      position: relative;
    }

    .step-number {
      font-size: 2.2rem;
      font-weight: 900;
      color: var(--primary-border);
      line-height: 1;
      margin-bottom: 14px;
    }

    .step-title {
      font-size: 1.1rem;
      font-weight: 700;
      margin-bottom: 8px;
    }

    .step-desc {
      font-size: 0.88rem;
      color: var(--text-muted);
    }

    /* Rating & Comparison Section */
    .rating-banner {
      background: linear-gradient(135deg, #1E2025 0%, #2D3139 100%);
      color: #FFFFFF;
      border-radius: var(--radius-lg);
      padding: 40px;
      margin-bottom: 40px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      flex-wrap: wrap;
      gap: 20px;
    }

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

    .score-num {
      font-size: 3.5rem;
      font-weight: 900;
      color: var(--primary-color);
      line-height: 1;
    }

    .score-stars {
      color: #FFC107;
      font-size: 1.4rem;
      margin-bottom: 4px;
    }

    .compare-table-wrapper {
      overflow-x: auto;
      background: var(--bg-white);
      border-radius: var(--radius-md);
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-sm);
    }

    .compare-table {
      width: 100%;
      border-collapse: collapse;
      text-align: left;
      min-width: 680px;
    }

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

    .compare-table th {
      background: #F8F9FC;
      font-weight: 700;
      color: var(--text-main);
    }

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

    .compare-table .highlight-col {
      background: var(--primary-light);
      font-weight: 700;
      color: var(--primary-color);
    }

    /* Testimonials */
    .review-card {
      background: var(--bg-white);
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      padding: 24px;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
    }

    .review-content {
      font-size: 0.95rem;
      color: var(--text-main);
      margin-bottom: 20px;
      font-style: italic;
    }

    .review-author {
      display: flex;
      align-items: center;
      gap: 12px;
    }

    .avatar-placeholder {
      width: 44px;
      height: 44px;
      border-radius: 50%;
      background: linear-gradient(135deg, #FF8800, #FF3300);
      color: #FFF;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
    }

    .author-info h4 {
      font-size: 0.95rem;
      font-weight: 700;
    }

    .author-info p {
      font-size: 0.8rem;
      color: var(--text-muted);
    }

    /* FAQ Accordion */
    .faq-list {
      max-width: 900px;
      margin: 0 auto;
      display: flex;
      flex-direction: column;
      gap: 14px;
    }

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

    .faq-item.active {
      border-color: var(--primary-border);
      box-shadow: var(--shadow-sm);
    }

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

    .faq-question::after {
      content: '+';
      font-size: 1.4rem;
      color: var(--primary-color);
      transition: var(--transition);
    }

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

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease-out;
      background: #FAFAFC;
    }

    .faq-answer-inner {
      padding: 0 24px 20px 24px;
      font-size: 0.95rem;
      color: var(--text-muted);
      line-height: 1.7;
    }

    /* Media Library Display Elements */
    .media-card-img {
      border-radius: var(--radius-md);
      overflow: hidden;
      margin-bottom: 16px;
      border: 1px solid var(--border-color);
    }

    /* Form Design */
    .form-wrapper {
      background: var(--bg-white);
      border: 1px solid var(--border-color);
      border-radius: var(--radius-lg);
      padding: 40px;
      box-shadow: var(--shadow-md);
    }

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

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

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

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

    .form-control {
      padding: 12px 16px;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-sm);
      font-size: 0.95rem;
      background: #FAFAFC;
      transition: var(--transition);
      outline: none;
    }

    .form-control:focus {
      border-color: var(--primary-color);
      background: #FFFFFF;
      box-shadow: 0 0 0 3px rgba(255, 85, 0, 0.1);
    }

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

    /* Footer Layout - Unified Single System */
    .site-footer {
      background: var(--bg-dark);
      color: #A0AEC0;
      padding: 70px 0 30px 0;
      border-top: 1px solid #2D3748;
    }

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

    .footer-col h4 {
      color: #FFFFFF;
      font-size: 1.1rem;
      font-weight: 700;
      margin-bottom: 20px;
    }

    .footer-links {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 10px;
    }

    .footer-links a {
      color: #A0AEC0;
      font-size: 0.9rem;
    }

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

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

    .friendship-links a {
      color: #CBD5E0;
      background: #2D3748;
      padding: 4px 12px;
      border-radius: 4px;
      font-size: 0.85rem;
    }

    .friendship-links a:hover {
      background: var(--primary-color);
      color: #FFF;
    }

    .footer-bottom {
      border-top: 1px solid #2D3748;
      padding-top: 24px;
      text-align: center;
      font-size: 0.88rem;
      color: #718096;
    }

    /* Floating Widget */
    .float-widget {
      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-color);
      color: #FFF;
      display: flex;
      align-items: center;
      justify-content: center;
      box-shadow: 0 4px 16px rgba(0,0,0,0.2);
      cursor: pointer;
      font-size: 1.2rem;
      border: none;
      transition: var(--transition);
    }

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

    /* Responsive Design */
    @media (max-width: 992px) {
      .grid-4, .grid-3 {
        grid-template-columns: repeat(2, 1fr);
      }
      .process-steps {
        grid-template-columns: repeat(2, 1fr);
      }
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
      .hero-h1 {
        font-size: 2rem;
      }
    }

    @media (max-width: 768px) {
      .nav-links {
        display: none;
        position: absolute;
        top: 72px;
        left: 0;
        right: 0;
        background: #FFFFFF;
        flex-direction: column;
        align-items: flex-start;
        padding: 20px;
        border-bottom: 1px solid var(--border-color);
        box-shadow: var(--shadow-md);
      }
      .nav-links.active {
        display: flex;
      }
      .nav-links li {
        width: 100%;
      }
      .nav-links li a {
        width: 100%;
        padding: 12px 16px;
      }
      .mobile-toggle {
        display: block;
      }
      .grid-4, .grid-3, .grid-2 {
        grid-template-columns: 1fr;
      }
      .process-steps {
        grid-template-columns: 1fr;
      }
      .form-grid {
        grid-template-columns: 1fr;
      }
      .form-group.full {
        grid-column: span 1;
      }
      .hero-stats {
        grid-template-columns: repeat(2, 1fr);
      }
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }