/* roulang page: index */
:root {
      --primary: #1A5F7A;
      --primary-light: rgba(26, 95, 122, 0.1);
      --secondary-bg: #F0F4F8;
      --accent: #E67E22;
      --accent-hover: #D35400;
      --text-dark: #1E293B;
      --text-muted: #64748B;
      --success: #10B981;
      --white: #FFFFFF;
      --border-light: #E2E8F0;
      --footer-bg: #1E293B;
      --footer-text: #CBD5E1;
      --footer-link: #94A3B8;
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 6px;
      --radius-container: 16px;
      --shadow-sm: 0 4px 20px rgba(0,0,0,0.04);
      --shadow-hover: 0 8px 30px rgba(0,0,0,0.08);
      --font-ping: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
      --transition: 0.3s ease;
      --nav-brand-height: 64px;
      --nav-channel-height: 48px;
    }
    * {
      box-sizing: border-box;
    }
    body {
      margin: 0;
      font-family: var(--font-ping);
      background: var(--white);
      color: var(--text-dark);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    h1, h2, h3, h4 {
      margin: 0;
      font-weight: 700;
      line-height: 1.3;
    }
    a {
      text-decoration: none;
      color: var(--primary);
      transition: color 0.2s;
    }
    a:hover {
      color: var(--accent-hover);
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 20px;
    }
    /* 导航系统 */
    .nav-wrapper {
      position: sticky;
      top: 0;
      z-index: 50;
      background: var(--white);
      transition: box-shadow 0.3s;
    }
    .nav-scrolled {
      box-shadow: 0 2px 8px rgba(0,0,0,0.06);
    }
    .brand-row {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: var(--nav-brand-height);
      border-bottom: 1px solid var(--border-light);
      padding: 0 20px;
      background: var(--white);
    }
    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--primary);
      letter-spacing: 1px;
    }
    .logo span {
      color: var(--accent);
    }
    .channel-row {
      background: #F8FAFC;
      height: var(--nav-channel-height);
      display: flex;
      align-items: center;
      padding: 0 20px;
      overflow-x: auto;
      white-space: nowrap;
      border-bottom: 1px solid var(--border-light);
    }
    .channel-link {
      color: var(--text-muted);
      margin-right: 28px;
      font-size: 15px;
      font-weight: 500;
      padding: 12px 0;
      border-bottom: 2px solid transparent;
      transition: 0.2s;
    }
    .channel-link:hover, .channel-link.active {
      color: var(--primary);
      border-bottom-color: var(--primary);
    }
    .btn-primary {
      background: var(--accent);
      color: white;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      font-size: 16px;
      letter-spacing: 0.5px;
      display: inline-block;
      transition: background 0.2s, transform 0.2s;
      border: none;
      cursor: pointer;
    }
    .btn-primary:hover {
      background: var(--accent-hover);
      color: white;
      transform: translateY(-1px);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      display: inline-block;
      transition: 0.2s;
    }
    .btn-outline:hover {
      background: var(--primary-light);
    }
    .mobile-menu-icon {
      display: none;
      font-size: 28px;
      color: var(--primary);
      cursor: pointer;
    }
    /* 移动端频道折叠 */
    @media (max-width: 768px) {
      .channel-row {
        display: none;
        flex-direction: column;
        align-items: flex-start;
        height: auto;
        background: white;
        padding: 15px 20px;
        position: absolute;
        top: var(--nav-brand-height);
        left: 0;
        right: 0;
        box-shadow: var(--shadow-hover);
        z-index: 40;
      }
      .channel-row.open {
        display: flex;
      }
      .channel-link {
        margin: 8px 0;
        padding: 6px 0;
        border-bottom: none;
      }
      .mobile-menu-icon {
        display: block;
      }
    }
    /* Hero */
    .hero {
      height: 100vh;
      min-height: 600px;
      display: flex;
      align-items: center;
      background: var(--secondary-bg);
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 40px;
      align-items: center;
      width: 100%;
    }
    .hero-image img {
      width: 100%;
      height: 480px;
      object-fit: cover;
      border-radius: var(--radius-container);
      box-shadow: 0 15px 30px rgba(0,0,0,0.1);
    }
    .hero h1 {
      font-size: 40px;
      margin-bottom: 20px;
      color: var(--text-dark);
    }
    .hero .sub {
      font-size: 20px;
      color: var(--text-muted);
      margin-bottom: 30px;
      line-height: 1.6;
    }
    @media (max-width: 768px) {
      .hero {
        height: auto;
        padding: 60px 0;
      }
      .hero-grid {
        grid-template-columns: 1fr;
        text-align: center;
      }
      .hero-image img {
        height: 300px;
        order: -1;
      }
      .hero h1 {
        font-size: 32px;
      }
    }
    /* 通用区块 */
    section {
      padding: 100px 0;
    }
    @media (max-width: 768px) {
      section {
        padding: 60px 0;
      }
    }
    .bg-light {
      background: var(--secondary-bg);
    }
    .section-title {
      text-align: center;
      margin-bottom: 50px;
    }
    .section-title h2 {
      font-size: 32px;
      color: var(--text-dark);
    }
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 24px;
    }
    .grid-4 {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      gap: 24px;
    }
    @media (max-width: 1024px) {
      .grid-3, .grid-4 {
        grid-template-columns: repeat(2,1fr);
      }
    }
    @media (max-width: 520px) {
      .grid-3, .grid-4 {
        grid-template-columns: 1fr;
      }
    }
    .card {
      background: var(--white);
      border-radius: var(--radius-card);
      padding: 28px;
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
      height: 100%;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .pain-icon {
      width: 64px;
      height: 64px;
      border-radius: 12px;
      background: var(--secondary-bg);
      margin-bottom: 20px;
      object-fit: cover;
    }
    .solution-row {
      display: flex;
      align-items: center;
      gap: 50px;
      margin-bottom: 80px;
    }
    .solution-row.reverse {
      flex-direction: row-reverse;
    }
    .solution-img {
      flex: 1;
      border-radius: var(--radius-card);
      overflow: hidden;
    }
    .solution-img img {
      width: 100%;
      height: 320px;
      object-fit: cover;
    }
    .solution-text {
      flex: 1;
    }
    @media (max-width: 768px) {
      .solution-row, .solution-row.reverse {
        flex-direction: column;
      }
    }
    .metric-number {
      font-size: 48px;
      font-weight: 700;
      color: var(--success);
    }
    .testimonial-text {
      font-style: italic;
      margin-bottom: 20px;
      color: var(--text-dark);
    }
    .avatar {
      width: 48px;
      height: 48px;
      border-radius: 50%;
      object-fit: cover;
      margin-right: 12px;
    }
    /* FAQ */
    .faq-item {
      background: #F8FAFC;
      border-radius: 8px;
      margin-bottom: 12px;
      padding: 16px 20px;
      cursor: pointer;
      transition: 0.2s;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
    }
    .faq-answer {
      display: none;
      padding: 16px 20px;
      background: white;
      border-left: 3px solid var(--primary);
      margin-top: 10px;
      border-radius: 0 8px 8px 0;
    }
    .faq-item.active .faq-answer {
      display: block;
    }
    /* CTA */
    .cta-block {
      background: linear-gradient(135deg, #1A5F7A 0%, #1A5F7A10 100%);
      text-align: center;
      padding: 80px 20px;
      border-radius: var(--radius-container);
    }
    /* Footer */
    .footer {
      background: var(--footer-bg);
      color: var(--footer-text);
      padding: 60px 0 20px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 30px;
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
    }
    .copyright {
      text-align: center;
      margin-top: 40px;
      font-size: 14px;
      color: var(--footer-link);
    }