/* roulang page: index */
/* ----- 设计变量 & Reset ----- */
    :root {
      --primary: #1B3A5C;
      --primary-hover: #0F2A40;
      --secondary: #2C7DA0;
      --accent: #E9B13B;
      --bg: #FAFBFD;
      --card-bg: #FFFFFF;
      --text-main: #0D1B2A;
      --text-body: #2E3B4E;
      --text-muted: #5F6B7A;
      --border: #E2E8F0;
      --shadow-sm: 0px 4px 16px rgba(0, 0, 0, 0.04);
      --shadow-md: 0px 8px 24px rgba(0, 0, 0, 0.08);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-tag: 6px;
      --font-cn: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Noto Sans SC", sans-serif;
      --font-num: "Inter", "SF Pro Display", system-ui, sans-serif;
      --max-width: 1280px;
      --nav-height: 72px;
      --nav-height-mobile: 60px;
    }

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

    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }

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

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

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

    button, input, textarea {
      font-family: inherit;
    }

    /* 容器 */
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }

    @media (max-width: 768px) {
      .container {
        padding: 0 20px;
      }
    }

    /* ----- 导航 (白底平台) ----- */
    #nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--nav-height);
      background: #FFFFFF;
      border-bottom: 1px solid rgba(0,0,0,0.04);
      display: flex;
      align-items: center;
      z-index: 1000;
      transition: box-shadow 0.2s;
    }
    #nav.scrolled {
      box-shadow: var(--shadow-sm);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    .logo {
      font-weight: 700;
      font-size: 1.4rem;
      color: var(--primary);
      letter-spacing: 0.5px;
      white-space: nowrap;
    }
    .logo span {
      color: var(--secondary);
    }
    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-link {
      color: var(--text-body);
      font-weight: 500;
      font-size: 0.95rem;
      transition: color 0.2s;
    }
    .nav-link:hover {
      color: var(--primary);
    }
    .btn-primary {
      background: var(--primary);
      color: #FFFFFF;
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 0.9rem;
      border: none;
      cursor: pointer;
      transition: all 0.2s ease;
      display: inline-block;
      text-align: center;
      white-space: nowrap;
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      transform: translateY(-1px);
      box-shadow: var(--shadow-md);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 0.9rem;
      cursor: pointer;
      transition: all 0.2s;
      display: inline-block;
    }
    .btn-outline:hover {
      background: #EBF0F5;
    }
    .btn-accent {
      background: var(--accent);
      color: #0D1B2A;
      font-weight: 700;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      border: none;
      cursor: pointer;
      transition: 0.2s;
      display: inline-block;
    }
    .btn-accent:hover {
      filter: brightness(1.05);
      transform: translateY(-1px);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: transparent;
      border: none;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--primary);
      transition: 0.2s;
    }
    @media (max-width: 768px) {
      .nav-menu {
        position: fixed;
        top: 0;
        right: -100%;
        width: 70%;
        height: 100vh;
        background: #FFFFFF;
        flex-direction: column;
        padding: 80px 32px;
        gap: 28px;
        box-shadow: -4px 0 24px rgba(0,0,0,0.1);
        transition: right 0.3s ease;
        z-index: 999;
      }
      .nav-menu.active {
        right: 0;
      }
      .hamburger {
        display: flex;
        z-index: 1001;
      }
      .nav-cta-desktop {
        display: none;
      }
      .nav-cta-mobile {
        display: block;
      }
    }
    @media (min-width: 769px) {
      .nav-cta-mobile {
        display: none;
      }
    }

    /* ----- 区块通用 ----- */
    section {
      padding: 80px 0;
    }
    @media (max-width: 768px) {
      section {
        padding: 56px 0;
      }
    }
    .section-title {
      font-size: 30px;
      font-weight: 700;
      color: var(--text-main);
      margin-bottom: 16px;
      line-height: 1.3;
    }
    .section-sub {
      font-size: 16px;
      color: var(--text-muted);
      margin-bottom: 48px;
    }

    /* Hero */
    #hero {
      padding-top: calc(var(--nav-height) + 48px);
      background: var(--bg);
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 48px;
    }
    .hero-text {
      flex: 1;
    }
    .hero-text h1 {
      font-size: 40px;
      font-weight: 700;
      color: var(--text-main);
      line-height: 1.2;
      margin-bottom: 20px;
    }
    .hero-text p {
      font-size: 18px;
      color: var(--text-body);
      margin-bottom: 32px;
    }
    .hero-actions {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-visual {
      flex: 1;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      border-radius: var(--radius-card);
      min-height: 320px;
      box-shadow: var(--shadow-sm);
      position: relative;
      overflow: hidden;
    }
    .dashboard-preview {
      background: rgba(255,255,255,0.9);
      backdrop-filter: blur(6px);
      border-radius: var(--radius-card);
      padding: 24px;
      margin: 24px;
      box-shadow: var(--shadow-sm);
    }
    @media (max-width: 768px) {
      .hero-grid {
        flex-direction: column;
      }
      .hero-text h1 {
        font-size: 28px;
      }
    }

    /* 实时指标 */
    .metrics-grid {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      gap: 24px;
    }
    .metric-card {
      background: var(--card-bg);
      padding: 28px;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      text-align: center;
    }
    .metric-number {
      font-family: var(--font-num);
      font-size: 48px;
      font-weight: 700;
      color: var(--primary);
    }
    .metric-label {
      font-size: 14px;
      color: var(--text-muted);
      margin-top: 4px;
    }
    @media (max-width: 768px) {
      .metrics-grid {
        grid-template-columns: 1fr;
      }
    }

    /* 服务矩阵 */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 24px;
    }
    .service-card {
      background: var(--card-bg);
      padding: 32px 28px;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      transition: all 0.2s;
    }
    .service-card:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-2px);
    }
    .service-icon {
      font-size: 28px;
      color: var(--secondary);
      margin-bottom: 16px;
    }
    .service-card h3 {
      font-size: 20px;
      font-weight: 600;
      color: var(--text-main);
      margin-bottom: 8px;
    }
    @media (max-width: 1024px) {
      .services-grid {
        grid-template-columns: repeat(2,1fr);
      }
    }
    @media (max-width: 520px) {
      .services-grid {
        grid-template-columns: 1fr;
      }
    }

    /* 对比 */
    .comparison-row {
      display: flex;
      gap: 32px;
    }
    .compare-card {
      flex: 1;
      padding: 32px;
      border-radius: var(--radius-card);
    }
    .before {
      background: #f8f9fb;
    }
    .after {
      background: #eef3f9;
    }
    @media (max-width: 768px) {
      .comparison-row {
        flex-direction: column;
      }
    }

    /* 流程 */
    .steps {
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .step {
      text-align: center;
    }
    .step-circle {
      width: 48px;
      height: 48px;
      background: var(--primary);
      color: #fff;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 auto 12px;
      font-weight: 700;
    }
    @media (max-width: 768px) {
      .steps {
        flex-direction: column;
        gap: 32px;
      }
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border);
      padding: 16px 0;
      cursor: pointer;
    }
    .faq-question {
      font-weight: 600;
      display: flex;
      justify-content: space-between;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: 0.3s;
      color: var(--text-muted);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-top: 12px;
    }

    /* CTA 深色区 */
    #cta {
      background: var(--primary);
      color: #FFFFFF;
    }
    .cta-grid {
      display: flex;
      gap: 48px;
      align-items: center;
    }
    .cta-form input, .cta-form textarea {
      width: 100%;
      padding: 12px;
      border-radius: var(--radius-btn);
      border: 1px solid var(--border);
      margin-bottom: 12px;
    }
    @media (max-width: 768px) {
      .cta-grid {
        flex-direction: column;
      }
    }

    /* Footer */
    #footer {
      background: #fff;
      padding: 48px 0 24px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
    }