/* roulang page: index */
/* ----- 设计变量 ----- */
    :root {
      --primary: #4E6EF2;
      --primary-hover: #3A5CD8;
      --primary-light: #EEF1FD;
      --success: #00B578;
      --warning: #FF9F0A;
      --danger: #FA5151;
      --text-primary: #1F2329;
      --text-secondary: #86909C;
      --border-light: #E5E8EF;
      --bg-page: #F5F6FA;
      --bg-white: #FFFFFF;
      --shadow-card: 0 2px 8px rgba(0,0,0,0.04);
      --shadow-card-hover: 0 8px 24px rgba(0,0,0,0.08);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 8px;
      --transition: 0.2s cubic-bezier(0.25, 0.8, 0.25, 1.2);
      --container-max: 1200px;
      --nav-height: 64px;
    }

    /* ----- 全局重置 ----- */
    *, *::before, *::after {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }
    body {
      font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      background-color: var(--bg-page);
      color: var(--text-primary);
      line-height: 1.5;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color var(--transition);
    }
    ul {
      list-style: none;
    }
    button, input, textarea {
      font-family: inherit;
      font-size: inherit;
      outline: none;
    }
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }
    @media (max-width: 768px) {
      .container {
        padding: 0 20px;
      }
    }
    @media (max-width: 520px) {
      .container {
        padding: 0 16px;
      }
    }

    /* ----- 导航栏 ----- */
    .header {
      position: sticky;
      top: 0;
      z-index: 100;
      background: var(--bg-white);
      box-shadow: 0 1px 4px rgba(0,0,0,0.04);
      height: var(--nav-height);
      display: flex;
      align-items: center;
    }
    .nav {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    .logo {
      font-size: 1.5rem;
      font-weight: 700;
      color: var(--text-primary);
      letter-spacing: 0.5px;
      white-space: nowrap;
    }
    .logo span {
      color: var(--primary);
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 28px;
    }
    .nav-links a {
      font-size: 0.95rem;
      color: var(--text-primary);
      font-weight: 500;
      position: relative;
      padding: 6px 0;
      transition: color var(--transition);
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--primary);
      transition: width var(--transition);
    }
    .nav-links a:hover,
    .nav-links a:active {
      color: var(--primary);
    }
    .nav-links a:hover::after,
    .nav-links a.active::after {
      width: 100%;
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: transparent;
      border: none;
      padding: 8px;
      z-index: 110;
    }
    .hamburger span {
      display: block;
      width: 24px;
      height: 2.5px;
      background: var(--text-primary);
      border-radius: 4px;
      transition: all var(--transition);
    }
    .mobile-menu {
      display: none;
    }
    @media (max-width: 768px) {
      .nav-links {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .mobile-menu {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        background: var(--bg-white);
        flex-direction: column;
        justify-content: center;
        align-items: flex-start;
        padding: 32px 40px;
        gap: 28px;
        z-index: 105;
        display: none;
      }
      .mobile-menu.active {
        display: flex;
      }
      .mobile-menu a {
        font-size: 1.8rem;
        font-weight: 600;
        color: var(--text-primary);
      }
    }

    /* ----- 板块通用 ----- */
    section {
      padding: 80px 0;
    }
    @media (max-width: 768px) {
      section {
        padding: 60px 0;
      }
    }
    .section-title {
      font-size: 2rem;
      font-weight: 700;
      margin-bottom: 16px;
      color: var(--text-primary);
    }
    @media (max-width: 768px) {
      .section-title {
        font-size: 1.6rem;
      }
    }
    .section-sub {
      font-size: 1rem;
      color: var(--text-secondary);
      margin-bottom: 48px;
      max-width: 600px;
    }

    /* ----- 按钮体系 ----- */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      border-radius: var(--radius-btn);
      font-weight: 500;
      padding: 12px 28px;
      transition: all var(--transition);
      cursor: pointer;
      border: none;
      font-size: 1rem;
      gap: 8px;
      line-height: 1.2;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      box-shadow: 0 2px 8px rgba(78,110,242,0.2);
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      transform: translateY(-1px);
      box-shadow: 0 6px 16px rgba(78,110,242,0.35);
    }
    .btn-secondary {
      background: #F0F2F5;
      color: var(--text-primary);
    }
    .btn-secondary:hover {
      background: #E5E8EF;
    }
    .btn:focus-visible {
      box-shadow: 0 0 0 3px rgba(78,110,242,0.25);
    }

    /* ----- Hero ----- */
    .hero {
      background-color: var(--bg-page);
      background-image: radial-gradient(circle at 20% 30%, rgba(78,110,242,0.02) 0%, transparent 40%);
      padding: 80px 0 80px;
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 60px;
    }
    .hero-text {
      flex: 1;
    }
    .hero-text h1 {
      font-size: 2.8rem;
      font-weight: 700;
      line-height: 1.3;
      margin-bottom: 20px;
    }
    .hero-text .highlight {
      color: var(--primary);
    }
    .hero-desc {
      font-size: 1.1rem;
      color: var(--text-secondary);
      margin-bottom: 32px;
      max-width: 480px;
    }
    .hero-image {
      flex: 1;
      background: #E5E8EF;
      border-radius: 24px;
      overflow: hidden;
      box-shadow: var(--shadow-card-hover);
    }
    .hero-image img {
      width: 100%;
      height: auto;
      object-fit: cover;
    }
    @media (max-width: 768px) {
      .hero-grid {
        flex-direction: column;
        gap: 40px;
      }
      .hero-text h1 {
        font-size: 2rem;
      }
      .hero-image {
        width: 100%;
      }
    }

    /* ----- 卡片网格 ----- */
    .cards-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    @media (max-width: 768px) {
      .cards-grid {
        grid-template-columns: 1fr;
      }
    }
    .card {
      background: var(--bg-white);
      border-radius: var(--radius-card);
      padding: 28px 24px;
      box-shadow: var(--shadow-card);
      transition: all var(--transition);
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
    }
    .card-icon {
      width: 48px;
      height: 48px;
      background: var(--primary-light);
      border-radius: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      color: var(--primary);
      font-size: 1.5rem;
    }
    .card h3 {
      font-size: 1.2rem;
      font-weight: 600;
      margin-bottom: 10px;
    }
    .card p {
      color: var(--text-secondary);
      font-size: 0.95rem;
    }

    /* 服务卡片列表 */
    .service-list {
      display: flex;
      flex-direction: column;
      gap: 20px;
    }
    .service-item {
      background: var(--bg-white);
      border-radius: var(--radius-card);
      padding: 24px;
      display: flex;
      gap: 24px;
      align-items: center;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .service-item:hover {
      box-shadow: var(--shadow-card-hover);
    }
    .service-icon {
      font-size: 2rem;
      color: var(--primary);
    }
    @media (max-width: 768px) {
      .service-item {
        flex-direction: column;
        align-items: flex-start;
      }
    }

    /* 流程步骤条 */
    .steps {
      display: flex;
      justify-content: space-between;
      align-items: flex-start;
      position: relative;
      gap: 24px;
    }
    .steps::before {
      content: '';
      position: absolute;
      top: 28px;
      left: 0;
      right: 0;
      height: 2px;
      background: var(--border-light);
      z-index: 0;
    }
    .step {
      flex: 1;
      text-align: center;
      position: relative;
      z-index: 2;
      background: var(--bg-page);
    }
    .step-circle {
      width: 56px;
      height: 56px;
      border-radius: 50%;
      background: white;
      border: 2px solid var(--border-light);
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      font-size: 1.2rem;
      margin: 0 auto 16px;
      color: var(--text-secondary);
      transition: all var(--transition);
    }
    .step.active .step-circle {
      background: var(--primary);
      border-color: var(--primary);
      color: white;
    }
    @media (max-width: 768px) {
      .steps {
        flex-direction: column;
        align-items: flex-start;
      }
      .steps::before {
        display: none;
      }
      .step {
        display: flex;
        align-items: center;
        gap: 16px;
        text-align: left;
      }
    }

    /* 数据亮点 */
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
    }
    .stat-card {
      background: var(--bg-white);
      border-radius: var(--radius-card);
      padding: 28px;
      text-align: center;
      box-shadow: var(--shadow-card);
    }
    .stat-number {
      font-size: 2.4rem;
      font-weight: 700;
      color: var(--primary);
    }
    @media (max-width: 768px) {
      .stats-grid {
        grid-template-columns: 1fr 1fr;
      }
    }

    /* FAQ 手风琴 */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 18px 0;
    }
    .faq-question {
      width: 100%;
      background: transparent;
      border: none;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-size: 1rem;
      font-weight: 600;
      cursor: pointer;
      padding: 8px 0;
      color: var(--text-primary);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-secondary);
      font-size: 0.95rem;
    }
    .faq-answer.open {
      max-height: 200px;
      padding-top: 12px;
    }

    /* CTA 终极区域 */
    .cta-section {
      background: linear-gradient(135deg, #EEF1FD 0%, #F5F6FA 100%);
      border-radius: 32px;
      padding: 64px 24px;
      text-align: center;
    }

    /* 表单 */
    .contact-form {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 20px;
      max-width: 700px;
      margin: 0 auto;
    }
    .form-group {
      display: flex;
      flex-direction: column;
      gap: 8px;
    }
    .form-group label {
      font-size: 0.9rem;
      font-weight: 500;
    }
    .form-control {
      padding: 12px 16px;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-input);
      transition: border var(--transition);
      background: white;
    }
    .form-control:focus {
      border-color: var(--primary);
      box-shadow: 0 0 0 3px rgba(78,110,242,0.25);
    }
    @media (max-width: 768px) {
      .contact-form {
        grid-template-columns: 1fr;
      }
    }

    /* 页脚 */
    .footer {
      background: #1F2329;
      color: rgba(255,255,255,0.8);
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr;
      gap: 40px;
    }
    .footer a {
      color: rgba(255,255,255,0.7);
    }
    .footer a:hover {
      color: var(--primary);
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }