/* roulang page: index */
:root {
      --primary: #1A1A2E;
      --accent: #E94560;
      --accent-hover: #C23152;
      --bg-light: #F8F9FA;
      --white: #FFFFFF;
      --text-dark: #1A1A2E;
      --text-body: #4A4A4A;
      --text-muted: #6B7280;
      --border-light: #E5E7EB;
      --shadow-sm: 0 4px 20px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 30px rgba(0,0,0,0.08);
      --shadow-lg: 0 16px 40px rgba(0,0,0,0.12);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 6px;
      --transition: 0.25s ease;
      --font-stack: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
      --nav-height: 76px;
    }

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

    html {
      scroll-behavior: smooth;
      scroll-padding-top: var(--nav-height);
    }

    body {
      font-family: var(--font-stack);
      background-color: var(--bg-light);
      color: var(--text-body);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: color var(--transition);
    }

    .container {
      width: 100%;
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }

    /* 导航栏 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      background: rgba(255,255,255,0.85);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid rgba(255,255,255,0.3);
      transition: box-shadow var(--transition), background var(--transition);
      height: var(--nav-height);
    }

    .site-header.scrolled {
      background: rgba(255,255,255,0.95);
      box-shadow: 0 4px 20px rgba(0,0,0,0.06);
    }

    .nav-bar {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 100%;
    }

    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--primary);
      letter-spacing: 1px;
      display: flex;
      align-items: center;
      gap: 8px;
    }

    .logo i {
      color: var(--accent);
      font-size: 28px;
    }

    .nav-links {
      display: flex;
      gap: 36px;
      align-items: center;
    }

    .nav-links a {
      font-weight: 500;
      color: var(--text-dark);
      position: relative;
      padding: 8px 0;
      font-size: 15px;
      transition: color var(--transition);
    }

    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent);
      transition: width var(--transition);
    }

    .nav-links a:hover,
    .nav-links a.active {
      color: var(--accent);
    }

    .nav-links a:hover::after,
    .nav-links a.active::after {
      width: 100%;
    }

    .hamburger {
      display: none;
      background: none;
      border: none;
      font-size: 24px;
      color: var(--primary);
      cursor: pointer;
      padding: 10px;
      transition: color var(--transition);
    }

    .hamburger:hover {
      color: var(--accent);
    }

    @media (max-width: 768px) {
      .nav-links {
        position: fixed;
        top: var(--nav-height);
        left: 0;
        width: 100%;
        background: rgba(255,255,255,0.96);
        backdrop-filter: blur(15px);
        flex-direction: column;
        gap: 0;
        padding: 20px 0;
        box-shadow: 0 20px 30px rgba(0,0,0,0.08);
        transform: translateY(-120%);
        opacity: 0;
        transition: transform 0.35s ease, opacity 0.25s ease;
        pointer-events: none;
      }

      .nav-links.active {
        transform: translateY(0);
        opacity: 1;
        pointer-events: auto;
      }

      .nav-links a {
        padding: 16px 24px;
        width: 100%;
        border-bottom: 1px solid var(--border-light);
        font-size: 16px;
      }

      .hamburger {
        display: block;
      }
    }

    /* 按钮 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      padding: 12px 28px;
      font-weight: 600;
      border-radius: var(--radius-btn);
      transition: all var(--transition);
      cursor: pointer;
      border: 2px solid transparent;
      font-size: 15px;
      line-height: 1.2;
    }

    .btn-primary {
      background: var(--accent);
      color: white;
      border-color: var(--accent);
    }

    .btn-primary:hover {
      background: var(--accent-hover);
      border-color: var(--accent-hover);
      transform: translateY(-2px);
      box-shadow: 0 8px 18px rgba(233,69,96,0.3);
    }

    .btn-outline {
      background: transparent;
      border-color: var(--primary);
      color: var(--primary);
    }

    .btn-outline:hover {
      background: var(--primary);
      color: white;
      border-color: var(--primary);
    }

    /* Hero */
    .hero {
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      min-height: 100vh;
      display: flex;
      align-items: center;
      position: relative;
      color: white;
      margin-top: 0;
    }

    .hero::before {
      content: '';
      position: absolute;
      inset: 0;
      background: rgba(26,26,46,0.75);
    }

    .hero-content {
      position: relative;
      z-index: 2;
      max-width: 800px;
      margin-top: 40px;
    }

    .hero h1 {
      font-size: 48px;
      font-weight: 700;
      line-height: 1.2;
      margin-bottom: 20px;
      color: white;
    }

    .hero p {
      font-size: 18px;
      opacity: 0.9;
      margin-bottom: 32px;
      max-width: 600px;
    }

    @media (max-width: 768px) {
      .hero h1 {
        font-size: 32px;
      }
      .hero p {
        font-size: 16px;
      }
    }

    /* 板块通用 */
    .section {
      padding: 80px 0;
    }

    .section-title {
      text-align: center;
      margin-bottom: 48px;
    }

    .section-title h2 {
      font-size: 32px;
      font-weight: 700;
      color: var(--primary);
      margin-bottom: 12px;
    }

    .section-title p {
      color: var(--text-muted);
      max-width: 600px;
      margin: 0 auto;
    }

    /* 卡片网格 */
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }

    .card {
      background: var(--white);
      border-radius: var(--radius-card);
      padding: 32px 24px;
      box-shadow: var(--shadow-sm);
      transition: transform var(--transition), box-shadow var(--transition);
      display: flex;
      flex-direction: column;
      align-items: flex-start;
    }

    .card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-md);
    }

    .card-icon {
      font-size: 40px;
      color: var(--accent);
      margin-bottom: 20px;
    }

    .card h3 {
      font-size: 20px;
      font-weight: 600;
      color: var(--primary);
      margin-bottom: 12px;
    }

    @media (max-width: 1024px) {
      .grid-3 {
        grid-template-columns: repeat(2, 1fr);
      }
    }

    @media (max-width: 640px) {
      .grid-3 {
        grid-template-columns: 1fr;
      }
      .section {
        padding: 60px 0;
      }
    }

    /* 产品图文交替 */
    .feature-row {
      display: flex;
      align-items: center;
      gap: 60px;
      margin-bottom: 80px;
    }

    .feature-row.reverse {
      flex-direction: row-reverse;
    }

    .feature-img {
      flex: 1;
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-md);
    }

    .feature-img img {
      width: 100%;
      height: auto;
      object-fit: cover;
    }

    .feature-text {
      flex: 1;
    }

    .feature-text h3 {
      font-size: 26px;
      font-weight: 700;
      color: var(--primary);
      margin-bottom: 16px;
    }

    @media (max-width: 768px) {
      .feature-row, .feature-row.reverse {
        flex-direction: column;
        gap: 32px;
      }
    }

    /* 数据流程 */
    .steps {
      display: flex;
      justify-content: space-between;
      gap: 20px;
      flex-wrap: wrap;
    }

    .step-item {
      flex: 1;
      min-width: 160px;
      text-align: center;
      background: var(--white);
      padding: 28px 16px;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
    }

    .step-num {
      font-size: 40px;
      font-weight: 700;
      color: var(--accent);
      margin-bottom: 8px;
    }

    /* FAQ */
    .faq-item {
      background: var(--white);
      border-radius: var(--radius-card);
      margin-bottom: 12px;
      box-shadow: var(--shadow-sm);
      overflow: hidden;
    }

    .faq-question {
      width: 100%;
      background: none;
      border: none;
      padding: 20px 24px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      font-size: 17px;
      color: var(--primary);
      cursor: pointer;
      text-align: left;
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease, padding 0.25s;
      background: #f9fafb;
      padding: 0 24px;
      color: var(--text-body);
    }

    .faq-item.open .faq-answer {
      max-height: 200px;
      padding: 16px 24px;
    }

    .faq-icon {
      transition: transform 0.3s;
    }

    .faq-item.open .faq-icon {
      transform: rotate(45deg);
    }

    /* CTA */
    .cta-band {
      background: var(--primary);
      color: white;
      text-align: center;
      padding: 70px 20px;
      border-radius: var(--radius-card);
      margin: 0 24px;
    }

    .footer {
      background: var(--primary);
      color: #ccc;
      padding: 48px 0 24px;
      text-align: center;
    }