/* roulang page: index */
:root {
      --primary: #4E6EF2;
      --primary-light: rgba(78, 110, 242, 0.08);
      --green: #00B578;
      --orange: #FF9F0A;
      --red: #FA5151;
      --text: #1F2329;
      --gray: #86909C;
      --bg: #F5F6FA;
      --card: #FFFFFF;
      --footer-bg: #EBEDF2;
      --radius-sm: 8px;
      --radius: 12px;
      --radius-pill: 50px;
      --shadow-card: 0 2px 12px rgba(0,0,0,0.04);
      --shadow-card-hover: 0 4px 20px rgba(0,0,0,0.08);
      --transition: 250ms ease-out;
    }
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
      background: var(--bg);
      color: var(--text);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    img { max-width: 100%; height: auto; display: block; }
    a { text-decoration: none; color: inherit; }
    ul { list-style: none; }

    .container {
      max-width: 1200px;
      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%;
      z-index: 100;
      height: 72px;
      display: flex;
      align-items: center;
      transition: background 300ms, box-shadow 300ms;
      background: transparent;
    }
    .header.scrolled {
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      box-shadow: 0 1px 8px rgba(0,0,0,0.04);
    }
    .nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    .logo {
      font-weight: 700;
      font-size: 22px;
      color: var(--text);
      letter-spacing: 0.5px;
    }
    .logo span {
      color: var(--primary);
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-links a {
      font-size: 15px;
      color: var(--text);
      transition: color 200ms;
      font-weight: 500;
    }
    .nav-links a:hover { color: var(--primary); }
    .btn-primary {
      background: var(--primary);
      color: #fff;
      padding: 10px 24px;
      border-radius: var(--radius-pill);
      font-weight: 600;
      font-size: 15px;
      transition: transform 200ms, box-shadow 200ms;
      display: inline-block;
      border: none;
      cursor: pointer;
      box-shadow: 0 4px 10px rgba(78,110,242,0.25);
    }
    .btn-primary:hover {
      transform: translateY(-2px);
      box-shadow: 0 8px 20px rgba(78,110,242,0.35);
    }
    .btn-outline {
      background: #fff;
      color: var(--primary);
      padding: 10px 24px;
      border-radius: var(--radius-pill);
      font-weight: 600;
      font-size: 15px;
      transition: transform 200ms, box-shadow 200ms;
      display: inline-block;
      border: 1px solid var(--primary);
    }
    .btn-outline:hover {
      transform: translateY(-2px);
      box-shadow: 0 4px 14px rgba(78,110,242,0.15);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: none;
      border: none;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--text);
      border-radius: 2px;
      transition: 300ms;
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .header { height: 56px; }
    }
    .mobile-menu {
      position: fixed;
      top: 0;
      right: 0;
      width: 280px;
      height: 100vh;
      background: #fff;
      box-shadow: -4px 0 24px rgba(0,0,0,0.08);
      transform: translateX(100%);
      transition: transform 300ms ease;
      display: flex;
      flex-direction: column;
      padding: 32px 24px;
      z-index: 200;
    }
    .mobile-menu.open {
      transform: translateX(0);
    }
    .mobile-menu a {
      font-size: 18px;
      padding: 14px 0;
      font-weight: 500;
      border-bottom: 1px solid #f0f0f0;
    }

    /* 首屏 */
    .hero {
      padding: 140px 0 80px;
      display: flex;
      align-items: center;
      gap: 60px;
    }
    .hero-left { flex: 1; }
    .hero-right { flex: 1; }
    .hero-right img {
      border-radius: var(--radius);
      box-shadow: var(--shadow-card);
    }
    .hero h1 {
      font-size: 44px;
      font-weight: 700;
      line-height: 1.3;
      margin-bottom: 20px;
    }
    .hero p {
      font-size: 16px;
      color: var(--gray);
      margin-bottom: 32px;
      max-width: 480px;
    }
    @media (max-width: 768px) {
      .hero { flex-direction: column; padding: 100px 0 60px; gap: 36px; }
      .hero h1 { font-size: 30px; }
    }

    /* 通用区块 */
    section { padding: 80px 0; }
    .section-title {
      font-size: 30px;
      font-weight: 600;
      margin-bottom: 18px;
    }
    .section-sub {
      color: var(--gray);
      font-size: 16px;
      margin-bottom: 48px;
    }
    @media (max-width: 768px) {
      section { padding: 60px 0; }
      .section-title { font-size: 24px; }
    }

    /* 卡片网格 */
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 24px;
    }
    .grid-4 {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      gap: 24px;
    }
    .grid-2 {
      display: grid;
      grid-template-columns: repeat(2,1fr);
      gap: 24px;
    }
    @media (max-width: 768px) {
      .grid-3, .grid-4, .grid-2 { grid-template-columns: 1fr; }
    }

    .card {
      background: var(--card);
      border-radius: var(--radius);
      padding: 28px;
      box-shadow: var(--shadow-card);
      transition: transform 250ms, box-shadow 250ms;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
    }
    .icon-circle {
      width: 48px;
      height: 48px;
      background: var(--primary-light);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      color: var(--primary);
      font-size: 22px;
    }
    .card h3 { font-size: 20px; font-weight: 600; margin-bottom: 12px; }

    /* 流程 */
    .process-steps {
      display: flex;
      justify-content: space-between;
      position: relative;
    }
    .process-steps::before {
      content: '';
      position: absolute;
      top: 24px;
      left: 5%;
      width: 90%;
      height: 2px;
      background: #E0E3E8;
      z-index: 0;
    }
    .step {
      text-align: center;
      z-index: 1;
      background: var(--bg);
      padding: 0 12px;
    }
    .step-number {
      width: 48px;
      height: 48px;
      background: var(--primary);
      color: #fff;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 auto 16px;
      font-weight: 700;
      font-size: 20px;
    }
    @media (max-width: 768px) {
      .process-steps { flex-direction: column; gap: 32px; }
      .process-steps::before { display: none; }
    }

    /* 数据卡 */
    .data-card {
      background: var(--card);
      border-radius: var(--radius);
      padding: 32px;
      text-align: center;
      box-shadow: var(--shadow-card);
    }
    .data-number {
      font-size: 38px;
      font-weight: 700;
      color: var(--primary);
      margin-bottom: 8px;
    }

    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      background: var(--card);
      border-radius: var(--radius);
      margin-bottom: 12px;
      box-shadow: var(--shadow-card);
      overflow: hidden;
    }
    .faq-question {
      padding: 20px 24px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      font-size: 16px;
      user-select: none;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 300ms ease;
      padding: 0 24px;
      color: var(--text);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding: 0 24px 20px;
    }
    .faq-icon {
      font-size: 20px;
      color: var(--primary);
      transition: transform 300ms;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }

    /* CTA 横幅 */
    .cta-banner {
      background: var(--primary);
      border-radius: var(--radius);
      padding: 60px 40px;
      text-align: center;
      color: #fff;
    }
    .cta-banner h2 {
      font-size: 32px;
      font-weight: 600;
      margin-bottom: 16px;
    }
    .cta-banner p {
      opacity: 0.9;
      margin-bottom: 32px;
    }
    .btn-white {
      background: #fff;
      color: var(--primary);
      padding: 12px 32px;
      border-radius: var(--radius-pill);
      font-weight: 700;
      transition: transform 200ms;
      display: inline-block;
    }
    .btn-white:hover { transform: scale(1.03); }

    /* 页脚 */
    .footer {
      background: var(--footer-bg);
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
    }
    .footer a { color: var(--text); font-size: 14px; }
    .copyright {
      margin-top: 40px;
      font-size: 14px;
      color: var(--gray);
      text-align: center;
    }
    @media (max-width: 768px) {
      .footer-grid { grid-template-columns: 1fr; }
    }