/* CSS Base & Mint Fresh Theme (春绿薄荷清新风) */
    :root {
      --primary-color: #00B884;
      --primary-hover: #009E71;
      --primary-light: #E6F8F3;
      --primary-mint: #10B981;
      --accent-color: #059669;
      --text-main: #1E293B;
      --text-muted: #64748B;
      --bg-main: #F4FBF7;
      --bg-card: #FFFFFF;
      --border-color: #E2E8F0;
      --border-mint: #A7F3D0;
      --shadow-sm: 0 2px 8px rgba(0, 184, 132, 0.06);
      --shadow-hover: 0 12px 28px rgba(0, 184, 132, 0.15);
      --radius: 12px;
      --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    }

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

    html {
      scroll-behavior: smooth;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      background-color: var(--bg-main);
      color: var(--text-main);
      line-height: 1.6;
    }

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

    /* Typography & Section Titles */
    h1, h2, h3, h4 {
      color: #0F172A;
      font-weight: 700;
    }

    .section-header {
      text-align: center;
      margin-bottom: 48px;
    }

    .section-tag {
      display: inline-block;
      padding: 6px 16px;
      background: var(--primary-light);
      color: var(--primary-color);
      font-size: 14px;
      font-weight: 600;
      border-radius: 20px;
      margin-bottom: 12px;
      border: 1px solid var(--border-mint);
    }

    .section-title {
      font-size: 32px;
      line-height: 1.3;
      margin-bottom: 12px;
    }

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

    /* Standard Header / Navigation */
    .header-nav {
      position: sticky;
      top: 0;
      z-index: 1000;
      background: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(10px);
      border-bottom: 1px solid var(--border-color);
      box-shadow: 0 2px 10px rgba(0,0,0,0.03);
    }

    .nav-wrapper {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 76px;
    }

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

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

    .brand-title {
      font-size: 20px;
      font-weight: 800;
      color: var(--primary-color);
      text-decoration: none;
      letter-spacing: -0.5px;
    }

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

    .nav-links li a {
      display: inline-block;
      padding: 8px 14px;
      color: var(--text-main);
      text-decoration: none;
      font-size: 15px;
      font-weight: 500;
      transition: var(--transition);
      border-radius: 6px;
    }

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

    .nav-cta {
      display: flex;
      align-items: center;
      gap: 12px;
    }

    .btn-nav-primary {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 10px 20px;
      background-color: var(--primary-color);
      color: #FFFFFF !important;
      text-decoration: none;
      font-weight: 600;
      font-size: 14px;
      border-radius: 8px;
      transition: var(--transition);
      box-shadow: 0 4px 12px rgba(0, 184, 132, 0.25);
    }

    .btn-nav-primary:hover {
      background-color: var(--primary-hover);
      transform: translateY(-1px);
    }

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

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

    section:nth-child(even) {
      background-color: #FFFFFF;
    }

    /* Hero Section - STRICTLY NO IMAGES */
    #hero {
      padding: 100px 0 80px;
      background: linear-gradient(135deg, #F4FBF7 0%, #E6F8F3 50%, #FFFFFF 100%);
      overflow: hidden;
    }

    .hero-content {
      text-align: center;
      max-width: 900px;
      margin: 0 auto;
      position: relative;
      z-index: 2;
    }

    .hero-badge {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      padding: 8px 18px;
      background: #FFFFFF;
      border: 1px solid var(--border-mint);
      border-radius: 30px;
      color: var(--primary-color);
      font-size: 14px;
      font-weight: 600;
      margin-bottom: 24px;
      box-shadow: var(--shadow-sm);
    }

    /* H1改写：字数控制在 20 字以内 */
    .hero-title {
      font-size: 42px;
      line-height: 1.25;
      font-weight: 800;
      color: #0F172A;
      margin-bottom: 20px;
      letter-spacing: -0.5px;
    }

    .hero-sub {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 36px;
      line-height: 1.6;
    }

    .hero-actions {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 16px;
      margin-bottom: 48px;
      flex-wrap: wrap;
    }

    .btn-main-hero {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 14px 32px;
      background-color: var(--primary-color);
      color: #FFFFFF;
      font-size: 16px;
      font-weight: 700;
      text-decoration: none;
      border-radius: 10px;
      box-shadow: 0 6px 20px rgba(0, 184, 132, 0.3);
      transition: var(--transition);
    }

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

    .btn-sub-hero {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 14px 32px;
      background-color: #FFFFFF;
      color: var(--text-main);
      font-size: 16px;
      font-weight: 600;
      text-decoration: none;
      border-radius: 10px;
      border: 1px solid var(--border-color);
      transition: var(--transition);
    }

    .btn-sub-hero:hover {
      border-color: var(--primary-color);
      color: var(--primary-color);
    }

    .hero-metrics {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
      background: #FFFFFF;
      padding: 30px;
      border-radius: 16px;
      border: 1px solid var(--border-mint);
      box-shadow: 0 10px 30px rgba(0, 184, 132, 0.08);
    }

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

    .metric-value {
      font-size: 28px;
      font-weight: 800;
      color: var(--primary-color);
      margin-bottom: 4px;
    }

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

    /* Cards & Grids General */
    .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; }

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

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

    .card-icon {
      width: 48px;
      height: 48px;
      background: var(--primary-light);
      color: var(--primary-color);
      border-radius: 10px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 20px;
      font-weight: bold;
      margin-bottom: 18px;
    }

    .card-title {
      font-size: 18px;
      font-weight: 700;
      margin-bottom: 10px;
      color: #0F172A;
    }

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

    /* Model Tags Matrix */
    .model-tags-wrapper {
      display: flex;
      flex-wrap: wrap;
      gap: 10px;
      justify-content: center;
      margin-top: 24px;
    }

    .model-tag {
      padding: 6px 14px;
      background: #FFFFFF;
      border: 1px solid var(--border-color);
      border-radius: 6px;
      font-size: 13px;
      font-weight: 600;
      color: var(--text-main);
      transition: var(--transition);
    }

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

    /* Responsive Media Container */
    .ai-page-image {
      width: 100%;
      height: auto;
      border-radius: 12px;
      display: block;
      box-shadow: var(--shadow-sm);
    }

    /* Rating & Comparison Component */
    .rating-banner {
      background: linear-gradient(135deg, #E6F8F3 0%, #FFFFFF 100%);
      border: 1px solid var(--border-mint);
      border-radius: 16px;
      padding: 24px 32px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      margin-bottom: 32px;
    }

    .rating-score {
      display: flex;
      align-items: center;
      gap: 16px;
    }

    .score-num {
      font-size: 40px;
      font-weight: 900;
      color: var(--primary-color);
    }

    .score-stars {
      color: #F59E0B;
      font-size: 20px;
    }

    .table-container {
      width: 100%;
      overflow-x: auto;
      background: #FFFFFF;
      border-radius: 12px;
      border: 1px solid var(--border-color);
    }

    .compare-table {
      width: 100%;
      border-collapse: collapse;
      text-align: left;
      min-width: 600px;
    }

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

    .compare-table th {
      background: #F8FAFC;
      font-weight: 700;
      color: #0F172A;
    }

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

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

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

    .faq-item {
      background: #FFFFFF;
      border: 1px solid var(--border-color);
      border-radius: 10px;
      overflow: hidden;
      transition: var(--transition);
    }

    .faq-question {
      padding: 20px 24px;
      font-size: 16px;
      font-weight: 700;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      user-select: none;
      color: #0F172A;
    }

    .faq-question:hover {
      color: var(--primary-color);
    }

    .faq-icon {
      font-size: 18px;
      transition: transform 0.3s ease;
    }

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

    .faq-item.active {
      border-color: var(--border-mint);
    }

    .faq-item.active .faq-icon {
      transform: rotate(180deg);
    }

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

    /* Testimonials / Reviews */
    .review-card {
      background: #FFFFFF;
      border: 1px solid var(--border-color);
      border-radius: 12px;
      padding: 24px;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
    }

    .review-text {
      font-size: 14px;
      color: var(--text-main);
      margin-bottom: 20px;
      line-height: 1.6;
    }

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

    .user-avatar-text {
      width: 40px;
      height: 40px;
      border-radius: 50%;
      background: var(--primary-light);
      color: var(--primary-color);
      font-weight: 700;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .user-info h5 {
      font-size: 14px;
      font-weight: 700;
      color: #0F172A;
    }

    .user-info span {
      font-size: 12px;
      color: var(--text-muted);
    }

    /* Contact Form Layout */
    .contact-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 40px;
      align-items: start;
    }

    .contact-info-card {
      background: #FFFFFF;
      border: 1px solid var(--border-mint);
      border-radius: 16px;
      padding: 32px;
    }

    .info-list-item {
      display: flex;
      align-items: flex-start;
      gap: 16px;
      margin-bottom: 24px;
    }

    .info-icon {
      width: 40px;
      height: 40px;
      background: var(--primary-light);
      color: var(--primary-color);
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: bold;
    }

    .form-card {
      background: #FFFFFF;
      border: 1px solid var(--border-color);
      border-radius: 16px;
      padding: 32px;
      box-shadow: var(--shadow-sm);
    }

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

    .form-label {
      display: block;
      font-size: 14px;
      font-weight: 600;
      margin-bottom: 8px;
      color: #0F172A;
    }

    .form-input, .form-select, .form-textarea {
      width: 100%;
      padding: 12px 16px;
      border: 1px solid var(--border-color);
      border-radius: 8px;
      font-size: 14px;
      background: #F8FAFC;
      transition: var(--transition);
      outline: none;
    }

    .form-input:focus, .form-select:focus, .form-textarea:focus {
      border-color: var(--primary-color);
      background: #FFFFFF;
      box-shadow: 0 0 0 3px rgba(0, 184, 132, 0.1);
    }

    .btn-submit {
      width: 100%;
      padding: 14px;
      background-color: var(--primary-color);
      color: #FFFFFF;
      border: none;
      border-radius: 8px;
      font-size: 16px;
      font-weight: 700;
      cursor: pointer;
      transition: var(--transition);
    }

    .btn-submit:hover {
      background-color: var(--primary-hover);
    }

    /* Unified Footer */
    footer {
      background-color: #0F172A;
      color: #94A3B8;
      padding: 60px 0 30px;
      font-size: 14px;
    }

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

    .footer-col h4 {
      color: #FFFFFF;
      font-size: 16px;
      margin-bottom: 20px;
    }

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

    .footer-links li {
      margin-bottom: 10px;
    }

    .footer-links a {
      color: #94A3B8;
      text-decoration: none;
      transition: var(--transition);
    }

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

    .friend-links-area {
      border-top: 1px solid #1E293B;
      padding-top: 24px;
      margin-top: 24px;
    }

    .friend-links-area a {
      color: #64748B;
      text-decoration: none;
      margin-right: 16px;
      display: inline-block;
      margin-bottom: 8px;
      transition: var(--transition);
    }

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

    .copyright {
      border-top: 1px solid #1E293B;
      padding-top: 24px;
      text-align: center;
      font-size: 13px;
      color: #64748B;
    }

    /* Floating Widget */
    .float-widget {
      position: fixed;
      right: 20px;
      bottom: 20px;
      z-index: 999;
      display: flex;
      flex-direction: column;
      gap: 10px;
    }

    .widget-btn {
      width: 50px;
      height: 50px;
      background: var(--primary-color);
      color: #FFFFFF;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      text-decoration: none;
      box-shadow: 0 4px 16px rgba(0,0,0,0.15);
      transition: var(--transition);
      font-size: 12px;
      font-weight: bold;
      text-align: center;
      line-height: 1.2;
    }

    .widget-btn:hover {
      transform: scale(1.08);
      background: var(--primary-hover);
    }

    /* Article List Styling */
    .article-list {
      list-style: none;
    }

    .article-item {
      padding: 12px 0;
      border-bottom: 1px dashed var(--border-color);
      display: flex;
      justify-content: space-between;
      align-items: center;
    }

    .article-item a {
      color: var(--text-main);
      text-decoration: none;
      font-weight: 500;
      transition: var(--transition);
    }

    .article-item a:hover {
      color: var(--primary-color);
    }

    /* Responsive Breakpoints */
    @media (max-width: 992px) {
      .hero-metrics { grid-template-columns: repeat(2, 1fr); }
      .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }
      .contact-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }

    @media (max-width: 768px) {
      .nav-links {
        display: none;
        position: absolute;
        top: 76px;
        left: 0;
        width: 100%;
        background: #FFFFFF;
        flex-direction: column;
        padding: 20px;
        box-shadow: 0 10px 20px rgba(0,0,0,0.05);
        border-bottom: 1px solid var(--border-color);
      }
      .nav-links.show { display: flex; }
      .menu-toggle { display: block; }
      .hero-title { font-size: 28px; }
      .hero-metrics { grid-template-columns: 1fr; }
      .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr; }
    }