/* roulang page: index */
:root {
      --primary: #0F4C81;
      --primary-deep: #0B2B4A;
      --accent: #FF6B35;
      --accent-hover: #E55A2B;
      --bg: #F8FAFC;
      --card-bg: #FFFFFF;
      --text-heading: #0F172A;
      --text-body: #334155;
      --text-muted: #64748B;
      --text-light: #F1F5F9;
      --border-light: #E2E8F0;
      --shadow-card: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
      --shadow-hover: 0 10px 25px rgba(0,0,0,0.08), 0 4px 10px rgba(0,0,0,0.04);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-tag: 6px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
      --font-number: "Inter", "PingFang SC", "Microsoft YaHei", sans-serif;
      --nav-height: 72px;
    }

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

    html {
      scroll-behavior: smooth;
    }

    body {
      font-family: var(--font-sans);
      background-color: var(--bg);
      color: var(--text-body);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s ease;
    }

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      transition: all 0.25s ease;
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }

    /* 导航 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--nav-height);
      background: #FFFFFF;
      box-shadow: 0 1px 8px rgba(0,0,0,0.04);
      z-index: 1000;
      display: flex;
      align-items: center;
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    .logo {
      font-weight: 700;
      font-size: 24px;
      color: var(--primary);
      letter-spacing: -0.5px;
      display: flex;
      align-items: center;
      gap: 6px;
    }
    .logo span {
      color: var(--accent);
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-links a {
      font-weight: 500;
      color: var(--text-body);
      position: relative;
      padding: 8px 0;
      font-size: 15px;
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary);
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 3px;
      background: var(--accent);
      transition: width 0.2s ease;
    }
    .nav-links a:hover::after,
    .nav-links a.active::after {
      width: 100%;
    }
    .btn-primary {
      background: var(--accent);
      color: white;
      border-radius: var(--radius-btn);
      padding: 12px 28px;
      font-weight: 600;
      font-size: 15px;
      box-shadow: 0 4px 10px rgba(255,107,53,0.25);
    }
    .btn-primary:hover {
      background: var(--accent-hover);
      transform: translateY(-2px);
      box-shadow: 0 8px 18px rgba(255,107,53,0.35);
    }
    .btn-outline {
      border: 2px solid var(--primary);
      color: var(--primary);
      background: transparent;
      border-radius: var(--radius-btn);
      padding: 12px 28px;
      font-weight: 600;
      font-size: 15px;
    }
    .btn-outline:hover {
      background: var(--primary);
      color: white;
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--primary);
      border-radius: 2px;
      transition: 0.2s;
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: var(--nav-height);
      left: 0;
      width: 100%;
      background: white;
      flex-direction: column;
      padding: 24px;
      box-shadow: 0 8px 20px rgba(0,0,0,0.08);
      z-index: 999;
      gap: 20px;
    }
    .mobile-menu a {
      font-weight: 600;
      font-size: 18px;
      color: var(--text-heading);
      border-bottom: 1px solid var(--border-light);
      padding-bottom: 12px;
    }

    /* Hero */
    .hero {
      padding: calc(var(--nav-height) + 60px) 0 80px;
      background: linear-gradient(135deg, #F8FAFC 0%, #EFF6FF 100%);
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .hero-content h1 {
      font-size: 48px;
      font-weight: 700;
      line-height: 1.2;
      color: var(--text-heading);
      margin-bottom: 20px;
    }
    .hero-content h1 span {
      color: var(--accent);
    }
    .hero-sub {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 32px;
    }
    .hero-actions {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-image {
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      min-height: 380px;
      border-radius: 32px;
      box-shadow: var(--shadow-hover);
      position: relative;
      overflow: hidden;
    }
    .hero-image::after {
      content: '';
      position: absolute;
      inset: 0;
      background: linear-gradient(135deg, rgba(15,76,129,0.15) 0%, rgba(255,107,53,0.08) 100%);
    }

    /* 通用板块 */
    section {
      padding: 90px 0;
    }
    .section-title {
      text-align: center;
      margin-bottom: 48px;
    }
    .section-title h2 {
      font-size: 36px;
      font-weight: 600;
      color: var(--text-heading);
      margin-bottom: 12px;
    }
    .section-title p {
      color: var(--text-muted);
      font-size: 18px;
    }

    /* 服务卡片 4列 */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
    }
    .service-card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 28px 22px;
      box-shadow: var(--shadow-card);
      transition: all 0.25s;
      display: flex;
      flex-direction: column;
    }
    .service-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
    }
    .service-icon {
      width: 56px;
      height: 56px;
      background: #EFF6FF;
      border-radius: 16px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      color: var(--primary);
      font-size: 28px;
      transition: 0.2s;
    }
    .service-card:hover .service-icon {
      background: var(--accent);
      color: white;
    }
    .service-card h3 {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 10px;
      color: var(--text-heading);
    }
    .service-card p {
      color: var(--text-muted);
      font-size: 15px;
      margin-bottom: 16px;
      flex: 1;
    }
    .service-link {
      font-weight: 600;
      color: var(--accent);
      font-size: 15px;
    }

    /* 数据条 */
    .stats-band {
      background: #F1F5F9;
      padding: 60px 0;
    }
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 32px;
      text-align: center;
    }
    .stat-number {
      font-size: 42px;
      font-weight: 700;
      color: var(--accent);
      font-family: var(--font-number);
      line-height: 1.1;
    }
    .stat-label {
      color: var(--text-muted);
      font-size: 16px;
      margin-top: 8px;
    }

    /* 案例卡片 3列 */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .case-card {
      background: white;
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: 0.25s;
    }
    .case-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
    }
    .case-img {
      height: 200px;
      background-size: cover;
      background-position: center;
      position: relative;
    }
    .case-img.cover1 { background-image: url('/assets/images/coverpic/cover-1.webp'); }
    .case-img.cover2 { background-image: url('/assets/images/coverpic/cover-2.webp'); }
    .case-img.cover3 { background-image: url('/assets/images/coverpic/cover-3.webp'); }
    .case-tag {
      position: absolute;
      top: 12px;
      left: 12px;
      background: #E0E7FF;
      color: var(--primary);
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 13px;
      font-weight: 600;
    }
    .case-body {
      padding: 20px;
    }
    .case-body h3 {
      font-weight: 600;
      margin-bottom: 8px;
    }

    /* 流程步骤 */
    .steps-row {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
      position: relative;
    }
    .step-item {
      text-align: center;
      position: relative;
    }
    .step-circle {
      width: 48px;
      height: 48px;
      background: var(--primary);
      color: white;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      font-size: 20px;
      margin: 0 auto 16px;
      z-index: 2;
      position: relative;
    }
    .step-item h4 {
      font-weight: 600;
      margin-bottom: 8px;
    }
    .step-line {
      position: absolute;
      top: 24px;
      left: 62%;
      width: 76%;
      height: 2px;
      background: #CBD5E1;
      z-index: 1;
    }

    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
      display: flex;
      flex-direction: column;
      gap: 16px;
    }
    .faq-item {
      background: white;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      padding: 18px 24px;
      border-left: 4px solid transparent;
      transition: 0.2s;
    }
    .faq-item.active {
      border-left-color: var(--accent);
    }
    .faq-question {
      font-weight: 600;
      font-size: 18px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      color: var(--text-heading);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-muted);
      margin-top: 0;
    }
    .faq-item.active .faq-answer {
      max-height: 150px;
      margin-top: 12px;
    }

    /* CTA 横幅 */
    .cta-banner {
      background: var(--primary-deep);
      padding: 80px 0;
      text-align: center;
      color: white;
    }
    .cta-banner h2 {
      font-size: 36px;
      font-weight: 700;
      margin-bottom: 16px;
    }
    .cta-banner p {
      opacity: 0.85;
      margin-bottom: 32px;
    }

    /* Footer */
    .footer {
      background: var(--primary-deep);
      color: #CBD5E1;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
    }
    .footer h4 {
      color: white;
      margin-bottom: 16px;
    }
    .footer a {
      color: #CBD5E1;
      font-size: 14px;
      display: block;
      margin-bottom: 8px;
    }
    .copyright {
      border-top: 1px solid rgba(255,255,255,0.15);
      margin-top: 40px;
      padding-top: 20px;
      text-align: center;
      font-size: 14px;
    }

    @media (max-width: 1024px) {
      .services-grid { grid-template-columns: repeat(2,1fr); }
    }
    @media (max-width: 768px) {
      .nav-links, .header-btn { display: none; }
      .hamburger { display: flex; }
      .hero-grid { grid-template-columns: 1fr; }
      .hero-content h1 { font-size: 34px; }
      .stats-grid { grid-template-columns: repeat(2,1fr); }
      .cases-grid { grid-template-columns: 1fr; }
      .steps-row { grid-template-columns: 1fr; }
      .step-line { display: none; }
      .footer-grid { grid-template-columns: 1fr; }
      section { padding: 60px 0; }
    }