/* roulang page: index */
:root {
      --primary: #4E6EF2;
      --primary-dark: #3A5AD9;
      --green: #00B578;
      --orange: #FF9F0A;
      --red: #FA5151;
      --bg: #F5F6FA;
      --white: #FFFFFF;
      --text-dark: #1F2329;
      --text-muted: #86909C;
      --border-light: #E8EDF5;
      --shadow-sm: 0 2px 12px rgba(0,0,0,0.04);
      --shadow-hover: 0 4px 20px rgba(0,0,0,0.08);
      --radius-card: 12px;
      --radius-btn: 8px;
      --transition: 200ms ease;
      --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --container-max: 1200px;
      --header-height: 64px;
    }
    * {
      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-dark);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }
    @media (max-width: 768px) {
      .container {
        padding: 0 16px;
      }
    }
    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: var(--white);
      box-shadow: 0 1px 4px rgba(0,0,0,0.04);
      z-index: 100;
      height: var(--header-height);
      display: flex;
      align-items: center;
    }
    .nav {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    .logo {
      font-size: 22px;
      font-weight: 700;
      color: var(--text-dark);
      text-decoration: none;
      display: flex;
      align-items: center;
      gap: 8px;
      letter-spacing: -0.3px;
    }
    .logo-icon {
      width: 32px;
      height: 32px;
      background: var(--primary);
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-weight: 700;
      font-size: 18px;
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
    }
    .nav-links a {
      text-decoration: none;
      color: var(--text-dark);
      font-weight: 500;
      font-size: 16px;
      transition: color var(--transition);
      position: relative;
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary);
    }
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: all var(--transition);
      cursor: pointer;
      text-decoration: none;
      border: none;
      font-size: 16px;
      padding: 10px 24px;
      line-height: 1.4;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      transform: translateY(-1px);
      box-shadow: 0 4px 10px rgba(78,110,242,0.3);
    }
    .btn-outline {
      background: transparent;
      border: 1px solid var(--primary);
      color: var(--primary);
    }
    .btn-outline:hover {
      background: rgba(78,110,242,0.05);
      transform: translateY(-1px);
    }
    .btn-large {
      padding: 16px 40px;
      font-size: 18px;
      border-radius: 12px;
    }
    .btn-white {
      background: white;
      color: var(--primary);
      font-weight: 700;
    }
    .btn-white:hover {
      background: #f0f2ff;
      transform: translateY(-1px);
      box-shadow: 0 8px 16px rgba(0,0,0,0.1);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: none;
      border: none;
      padding: 4px;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--text-dark);
      border-radius: 2px;
      transition: 0.2s;
    }
    @media (max-width: 991px) {
      .nav-links {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .mobile-menu {
        position: fixed;
        top: var(--header-height);
        left: 0;
        width: 100%;
        background: white;
        box-shadow: 0 8px 20px rgba(0,0,0,0.08);
        flex-direction: column;
        padding: 24px;
        gap: 20px;
        display: none;
        z-index: 99;
      }
      .mobile-menu.active {
        display: flex;
      }
      .mobile-menu a {
        font-size: 18px;
        font-weight: 500;
        color: var(--text-dark);
        text-decoration: none;
      }
    }
    /* 区块通用 */
    section {
      padding: 80px 0;
    }
    @media (max-width: 768px) {
      section {
        padding: 60px 0;
      }
    }
    .section-title {
      font-size: 32px;
      font-weight: 600;
      line-height: 1.3;
      margin-bottom: 16px;
      color: var(--text-dark);
    }
    .section-lead {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 48px;
    }
    .text-center {
      text-align: center;
    }
    /* Hero */
    .hero {
      background: linear-gradient(135deg, #F5F6FA 0%, #E8EDF5 100%);
      min-height: 70vh;
      display: flex;
      align-items: center;
      justify-content: center;
      text-align: center;
      padding-top: var(--header-height);
      position: relative;
      overflow: hidden;
    }
    .hero-content {
      position: relative;
      z-index: 2;
      max-width: 800px;
      margin: 0 auto;
    }
    .hero h1 {
      font-size: 48px;
      font-weight: 700;
      line-height: 1.2;
      margin-bottom: 20px;
      color: var(--text-dark);
    }
    .hero p {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 32px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      justify-content: center;
      flex-wrap: wrap;
    }
    @media (max-width: 768px) {
      .hero h1 {
        font-size: 32px;
      }
      .hero-buttons .btn {
        width: 80%;
      }
    }
    /* 卡片网格 */
    .grid-4, .grid-3, .grid-2 {
      display: grid;
      gap: 24px;
    }
    .grid-4 { grid-template-columns: repeat(4, 1fr); }
    .grid-3 { grid-template-columns: repeat(3, 1fr); }
    @media (max-width: 991px) {
      .grid-4 { grid-template-columns: repeat(2, 1fr); }
    }
    @media (max-width: 600px) {
      .grid-4, .grid-3 { grid-template-columns: 1fr; }
    }
    .card {
      background: var(--white);
      border-radius: var(--radius-card);
      padding: 24px;
      box-shadow: var(--shadow-sm);
      transition: all var(--transition);
      height: 100%;
      display: flex;
      flex-direction: column;
    }
    .card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-2px);
    }
    .card-img {
      width: 100%;
      height: 200px;
      object-fit: cover;
      border-radius: var(--radius-card) var(--radius-card) 0 0;
      margin: -24px -24px 20px -24px;
      width: calc(100% + 48px);
      background: #E8EDF5;
    }
    .icon-circle {
      width: 56px;
      height: 56px;
      background: rgba(78,110,242,0.08);
      border-radius: 16px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 18px;
      color: var(--primary);
    }
    .card h3 {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 8px;
    }
    .card p {
      color: var(--text-muted);
      font-size: 14px;
      flex: 1;
    }
    .link-arrow {
      color: var(--primary);
      font-weight: 500;
      text-decoration: none;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      margin-top: 12px;
      font-size: 14px;
    }
    .link-arrow:hover {
      text-decoration: underline;
    }
    /* 数据块 */
    .data-bg {
      background: var(--bg);
    }
    .data-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 32px;
      text-align: center;
    }
    @media (max-width: 600px) {
      .data-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    .data-num {
      font-size: 48px;
      font-weight: 700;
      color: var(--text-dark);
    }
    .data-num.highlight {
      color: var(--orange);
    }
    .data-label {
      font-size: 14px;
      color: var(--text-muted);
    }
    /* 流程 */
    .process-steps {
      display: flex;
      justify-content: space-between;
      align-items: flex-start;
      position: relative;
    }
    .process-steps::before {
      content: '';
      position: absolute;
      top: 24px;
      left: 10%;
      width: 80%;
      height: 2px;
      background: #E8EDF5;
      z-index: 0;
    }
    .step {
      display: flex;
      flex-direction: column;
      align-items: center;
      text-align: center;
      z-index: 1;
      flex: 1;
    }
    .step-circle {
      width: 48px;
      height: 48px;
      border-radius: 50%;
      background: white;
      border: 2px solid var(--primary);
      color: var(--primary);
      font-weight: 700;
      font-size: 20px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 16px;
    }
    @media (max-width: 768px) {
      .process-steps {
        flex-direction: column;
        gap: 32px;
      }
      .process-steps::before {
        display: none;
      }
    }
    /* FAQ */
    .faq-item {
      background: white;
      border-radius: var(--radius-card);
      margin-bottom: 12px;
      box-shadow: var(--shadow-sm);
      overflow: hidden;
    }
    .faq-question {
      padding: 20px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      background: white;
      transition: background 0.2s;
    }
    .faq-question:hover {
      background: #F8F9FC;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s ease;
      background: #FAFBFC;
      color: var(--text-muted);
      font-size: 14px;
      padding: 0 20px;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      padding: 20px;
    }
    .faq-arrow {
      transition: transform 0.3s;
    }
    .faq-item.open .faq-arrow {
      transform: rotate(180deg);
    }
    /* CTA */
    .cta-dark {
      background: #1F2329;
      color: white;
      text-align: center;
    }
    .cta-dark h2 {
      font-size: 32px;
      font-weight: 600;
      margin-bottom: 12px;
    }
    .cta-sub {
      color: #B0B8C1;
      margin-bottom: 32px;
    }
    /* 页脚 */
    .footer {
      background: white;
      padding: 48px 0 24px;
      border-top: 1px solid var(--border-light);
    }
    .footer-grid {
      display: flex;
      justify-content: space-between;
      flex-wrap: wrap;
      gap: 32px;
      margin-bottom: 32px;
    }
    .footer-links a {
      display: block;
      color: var(--text-muted);
      text-decoration: none;
      margin-bottom: 8px;
      font-size: 14px;
    }
    .footer-links a:hover {
      color: var(--primary);
    }
    .copyright {
      font-size: 14px;
      color: var(--text-muted);
      text-align: center;
    }
    @media (max-width: 768px) {
      .footer-grid {
        flex-direction: column;
      }
    }