/* roulang page: index */
* {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    :root {
      --primary: #0F2B46;
      --primary-light: #1A3F63;
      --accent: #00A3A3;
      --accent-light: #00C9C9;
      --warm: #FF6B35;
      --bg: #F8FAFC;
      --card-bg: #FFFFFF;
      --alt-bg: #F1F5F9;
      --dark-bg: #0F2B46;
      --text-heading: #0A1929;
      --text-body: #334155;
      --text-muted: #64748B;
      --text-white: #FFFFFF;
      --border: #E2E8F0;
      --border-dark: rgba(255, 255, 255, 0.12);
      --shadow-card: 0 4px 20px rgba(15, 43, 70, 0.06), 0 1px 3px rgba(15, 43, 70, 0.04);
      --shadow-hover: 0 12px 32px rgba(15, 43, 70, 0.08), 0 4px 8px rgba(15, 43, 70, 0.04);
      --shadow-nav: 0 2px 12px rgba(15, 43, 70, 0.08);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-badge: 20px;
      --transition: all 0.25s ease;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
      --font-number: "Inter", "SF Pro Text", system-ui, sans-serif;
    }
    body {
      font-family: var(--font-sans);
      background: var(--bg);
      color: var(--text-body);
      line-height: 1.7;
      font-size: 16px;
      scroll-behavior: smooth;
    }
    h1, h2, h3, h4 {
      color: var(--text-heading);
      letter-spacing: -0.02em;
      font-weight: 700;
    }
    h1 { font-size: 36px; line-height: 1.2; }
    h2 { font-size: 28px; line-height: 1.3; }
    h3 { font-size: 22px; line-height: 1.4; font-weight: 600; }
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      transition: var(--transition);
      background: rgba(255,255,255,0.85);
      backdrop-filter: blur(6px);
      box-shadow: none;
    }
    .header.scrolled {
      background: rgba(255,255,255,0.98);
      box-shadow: var(--shadow-nav);
    }
    .nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--primary);
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .logo i {
      color: var(--accent);
      font-size: 28px;
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
      list-style: none;
    }
    .nav-links a {
      font-size: 15px;
      font-weight: 500;
      color: var(--text-body);
      position: relative;
      padding: 4px 0;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent);
      transition: width 0.2s ease;
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--accent);
    }
    .nav-links a:hover::after,
    .nav-links a.active::after {
      width: 100%;
    }
    .btn-primary {
      background: var(--accent);
      color: white;
      border: none;
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 15px;
      cursor: pointer;
      transition: var(--transition);
      display: inline-flex;
      align-items: center;
      gap: 6px;
      box-shadow: 0 2px 6px rgba(0,163,163,0.2);
    }
    .btn-primary:hover {
      background: var(--accent-light);
      box-shadow: 0 6px 16px rgba(0,163,163,0.35);
      transform: translateY(-1px);
    }
    .hamburger {
      display: none;
      background: none;
      border: none;
      font-size: 24px;
      color: var(--primary);
      cursor: pointer;
    }
    /* 英雄区 */
    .hero {
      padding: 140px 0 100px;
      background: var(--bg);
      position: relative;
      overflow: hidden;
    }
    .hero::before {
      content: "";
      position: absolute;
      right: -80px;
      top: -40px;
      width: 600px;
      height: 600px;
      background: radial-gradient(circle, rgba(0,163,163,0.08) 0%, rgba(15,43,70,0.04) 40%, transparent 70%);
      border-radius: 50%;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
      position: relative;
      z-index: 2;
    }
    .hero-text h1 {
      font-size: 44px;
      margin-bottom: 20px;
      color: var(--primary);
    }
    .hero-text p {
      font-size: 17px;
      color: var(--text-muted);
      margin-bottom: 32px;
      max-width: 480px;
    }
    .hero-image img {
      border-radius: 24px;
      box-shadow: 0 20px 40px rgba(15,43,70,0.15);
      width: 100%;
      object-fit: cover;
    }
    .btn-ghost {
      background: transparent;
      border: 1px solid var(--primary);
      color: var(--primary);
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      margin-left: 16px;
      transition: var(--transition);
    }
    .btn-ghost:hover {
      background: var(--primary);
      color: white;
    }
    /* 通用区块 */
    section {
      padding: 80px 0;
    }
    .section-title {
      text-align: center;
      margin-bottom: 48px;
    }
    .section-title h2 {
      color: var(--primary);
      margin-bottom: 12px;
    }
    .section-title p {
      color: var(--text-muted);
      max-width: 620px;
      margin: 0 auto;
    }
    /* 核心优势 */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 32px;
    }
    .feature-card {
      background: var(--card-bg);
      padding: 36px 28px;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      transition: var(--transition);
      border: 1px solid transparent;
    }
    .feature-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
      border-color: rgba(0,163,163,0.15);
    }
    .feature-icon {
      font-size: 36px;
      color: var(--accent);
      margin-bottom: 20px;
    }
    .feature-card h3 {
      margin-bottom: 12px;
    }
    /* 解决方案 */
    .solution-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
      margin-bottom: 80px;
    }
    .solution-content h3 {
      font-size: 26px;
      margin-bottom: 16px;
    }
    .solution-number {
      font-size: 48px;
      font-weight: 700;
      color: rgba(0,163,163,0.15);
      margin-bottom: 8px;
    }
    .solution-list {
      list-style: none;
      margin: 20px 0;
    }
    .solution-list li {
      display: flex;
      align-items: center;
      gap: 10px;
      margin-bottom: 10px;
      color: var(--text-body);
    }
    .solution-list i {
      color: var(--accent);
    }
    .solution-image img {
      border-radius: 20px;
    }
    /* 数据 */
    .data-section {
      background: var(--alt-bg);
      border-radius: 32px;
      margin: 0 24px;
    }
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      text-align: center;
      gap: 24px;
    }
    .stat-number {
      font-size: 42px;
      font-weight: 700;
      color: var(--warm);
      font-family: var(--font-number);
    }
    .stat-label {
      color: var(--text-muted);
      margin-top: 8px;
    }
    /* 案例 */
    .cases-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 32px;
    }
    .case-card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
      display: flex;
      flex-direction: column;
    }
    .case-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .case-img img {
      height: 200px;
      object-fit: cover;
      width: 100%;
    }
    .case-body {
      padding: 24px;
    }
    .badge {
      display: inline-block;
      border: 1px solid var(--accent);
      color: var(--accent);
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 13px;
      margin-bottom: 12px;
    }
    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border);
      padding: 20px 0;
    }
    .faq-question {
      display: flex;
      align-items: center;
      gap: 16px;
      font-weight: 600;
      font-size: 17px;
      cursor: pointer;
      color: var(--primary);
    }
    .faq-question span {
      color: var(--accent);
      font-weight: 700;
      font-size: 20px;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      padding-left: 36px;
      color: var(--text-body);
    }
    .faq-item.active .faq-answer {
      max-height: 150px;
      margin-top: 12px;
    }
    /* CTA */
    .cta-dark {
      background: var(--dark-bg);
      text-align: center;
      border-radius: 28px;
      margin: 0 24px;
      color: white;
    }
    .cta-dark h2 {
      color: white;
      font-size: 32px;
    }
    .btn-outline-white {
      border: 1px solid white;
      color: white;
      background: transparent;
      padding: 10px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      margin-left: 16px;
      transition: var(--transition);
    }
    .btn-outline-white:hover {
      background: white;
      color: var(--primary);
    }
    /* 页脚 */
    .footer {
      background: var(--dark-bg);
      color: #E2E8F0;
      padding: 60px 0 20px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
    }
    .footer-logo {
      font-size: 22px;
      font-weight: 700;
      color: white;
    }
    .footer a {
      color: #CBD5E1;
      display: block;
      margin-bottom: 8px;
    }
    .footer a:hover {
      color: var(--accent-light);
    }
    .copyright {
      border-top: 1px solid var(--border-dark);
      margin-top: 40px;
      padding-top: 20px;
      text-align: center;
      color: #94A3B8;
      font-size: 14px;
    }
    @media (max-width: 992px) {
      .hero-grid, .solution-row { grid-template-columns: 1fr; }
      .features-grid { grid-template-columns: repeat(2,1fr); }
      .stats-grid { grid-template-columns: repeat(2,1fr); }
      .cases-grid { grid-template-columns: 1fr; }
    }
    @media (max-width: 768px) {
      .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 80%;
        height: 100vh;
        background: white;
        flex-direction: column;
        justify-content: center;
        transition: 0.3s;
        box-shadow: -4px 0 20px rgba(0,0,0,0.1);
        gap: 24px;
      }
      .nav-links.open { right: 0; }
      .hamburger { display: block; z-index: 1001; }
      .features-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
      h1 { font-size: 32px; }
    }