/* roulang page: index */
:root {
      --primary: #0F172A;
      --primary-light: #1E293B;
      --accent: #10B981;
      --accent-hover: #059669;
      --cyan: #06B6D4;
      --bg-light: #F8FAFC;
      --bg-white: #FFFFFF;
      --bg-dark: #0B0F19;
      --text-main: #0F172A;
      --text-muted: #475569;
      --text-light: #94A3B8;
      --border-color: #E2E8F0;
      --border-dark: #1E293B;
      --radius: 10px;
      --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
      --shadow-md: 0 6px 24px -2px rgba(15, 23, 42, 0.08);
      --shadow-accent: 0 12px 28px -4px rgba(16, 185, 129, 0.2);
      --transition: all 0.25s ease-in-out;
    }

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

    html {
      scroll-behavior: smooth;
      font-family: system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;
      background-color: var(--bg-light);
      color: var(--text-main);
      line-height: 1.65;
    }

    body {
      overflow-x: hidden;
      -webkit-font-smoothing: antialiased;
    }

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

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

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

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 1.5rem;
    }

    /* Topbar */
    .topbar {
      background-color: var(--bg-dark);
      color: var(--text-light);
      font-size: 0.85rem;
      border-bottom: 1px solid var(--border-dark);
    }
    .topbar-content {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 0.5rem 0;
    }
    .topbar-info span {
      margin-right: 1.5rem;
    }

    /* Main Navigation */
    .navbar {
      position: sticky;
      top: 0;
      z-index: 100;
      background: rgba(255, 255, 255, 0.92);
      backdrop-filter: blur(10px);
      border-bottom: 1px solid var(--border-color);
    }
    .navbar-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .brand-logo {
      font-size: 1.35rem;
      font-weight: 800;
      color: var(--primary);
      display: flex;
      align-items: center;
      gap: 0.5rem;
      letter-spacing: -0.5px;
    }
    .brand-badge {
      font-size: 0.75rem;
      background: rgba(16, 185, 129, 0.15);
      color: var(--accent);
      padding: 2px 6px;
      border-radius: 4px;
      font-weight: 700;
    }
    .nav-links {
      display: flex;
      gap: 1.75rem;
      list-style: none;
    }
    .nav-links a {
      font-weight: 600;
      color: var(--text-muted);
      font-size: 0.95rem;
    }
    .nav-links a:hover {
      color: var(--accent);
    }
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-weight: 600;
      border-radius: 6px;
      padding: 0.7rem 1.4rem;
      transition: var(--transition);
      cursor: pointer;
      border: 1px solid transparent;
      font-size: 0.95rem;
    }
    .btn-primary {
      background-color: var(--accent);
      color: #FFFFFF;
      box-shadow: var(--shadow-accent);
    }
    .btn-primary:hover {
      background-color: var(--accent-hover);
      transform: translateY(-1px);
    }
    .btn-outline {
      border-color: var(--border-color);
      background: transparent;
      color: var(--text-main);
    }
    .btn-outline:hover {
      border-color: var(--accent);
      color: var(--accent);
      background: rgba(16, 185, 129, 0.04);
    }
    .btn-dark {
      background-color: var(--primary);
      color: #FFFFFF;
    }
    .btn-dark:hover {
      background-color: var(--primary-light);
    }

    /* Section Utility */
    section {
      padding: 85px 0;
      position: relative;
    }
    .section-light {
      background-color: var(--bg-light);
    }
    .section-white {
      background-color: var(--bg-white);
    }
    .section-dark {
      background-color: var(--bg-dark);
      color: #FFFFFF;
    }
    .section-header {
      margin-bottom: 3.5rem;
    }
    .section-tag {
      display: inline-block;
      font-size: 0.8rem;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 1px;
      color: var(--accent);
      margin-bottom: 0.75rem;
      padding: 3px 10px;
      background: rgba(16, 185, 129, 0.1);
      border-radius: 20px;
    }
    .section-title {
      font-size: 2.1rem;
      font-weight: 800;
      line-height: 1.25;
      margin-bottom: 1rem;
      color: var(--text-main);
    }
    .section-dark .section-title {
      color: #FFFFFF;
    }
    .section-desc {
      font-size: 1.05rem;
      color: var(--text-muted);
      max-width: 680px;
    }
    .section-dark .section-desc {
      color: var(--text-light);
    }

    /* Hero Section: 5:7 斜向错位大图版式 */
    .hero-section {
      background: radial-gradient(circle at top right, #1E293B, #0F172A);
      color: #FFFFFF;
      padding: 90px 0 110px 0;
      overflow: hidden;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 5fr 7fr;
      gap: 3.5rem;
      align-items: center;
    }
    .hero-content h1 {
      font-size: 2.75rem;
      font-weight: 800;
      line-height: 1.2;
      margin-bottom: 1.25rem;
      letter-spacing: -0.5px;
    }
    .hero-content h1 span {
      color: var(--accent);
    }
    .hero-p {
      font-size: 1.05rem;
      color: var(--text-light);
      margin-bottom: 2rem;
      line-height: 1.75;
    }
    .hero-cta-group {
      display: flex;
      gap: 1rem;
      margin-bottom: 2.5rem;
    }
    .hero-kpis {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 1.5rem;
      border-top: 1px solid var(--border-dark);
      padding-top: 1.5rem;
    }
    .hero-kpi-item h4 {
      font-size: 1.6rem;
      font-weight: 800;
      color: var(--cyan);
      font-family: 'DIN Alternate', Inter, sans-serif;
    }
    .hero-kpi-item p {
      font-size: 0.85rem;
      color: var(--text-light);
    }
    .hero-stage {
      position: relative;
      transform: perspective(1000px) rotateY(-4deg) rotateX(2deg);
      transition: var(--transition);
    }
    .hero-stage:hover {
      transform: perspective(1000px) rotateY(0deg) rotateX(0deg);
    }
    .hero-img-wrap {
      border-radius: var(--radius);
      overflow: hidden;
      box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
      border: 1px solid rgba(255, 255, 255, 0.1);
    }
    .hero-img-wrap img {
      width: 100%;
      height: 480px;
      object-fit: cover;
    }

    /* Cards Grid */
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 2rem;
    }
    .grid-2 {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 2.5rem;
    }
    .grid-4 {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 1.5rem;
    }

    .card {
      background: var(--bg-white);
      border-radius: var(--radius);
      padding: 2rem;
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
    }
    .card:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-4px);
      border-color: rgba(16, 185, 129, 0.4);
    }
    .card-icon {
      width: 48px;
      height: 48px;
      background: rgba(16, 185, 129, 0.1);
      color: var(--accent);
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 800;
      font-size: 1.25rem;
      margin-bottom: 1.25rem;
    }
    .card h3 {
      font-size: 1.25rem;
      font-weight: 700;
      margin-bottom: 0.75rem;
      color: var(--text-main);
    }
    .card p {
      font-size: 0.95rem;
      color: var(--text-muted);
      line-height: 1.6;
    }
    .card-footer-data {
      margin-top: 1.25rem;
      padding-top: 1rem;
      border-top: 1px dashed var(--border-color);
      font-size: 0.85rem;
      color: var(--accent);
      font-weight: 700;
    }

    /* Challenge Grid vs Solution */
    .challenge-card {
      background: #FFF1F2;
      border: 1px solid #FFE4E6;
      border-radius: var(--radius);
      padding: 1.75rem;
    }
    .challenge-card h4 {
      color: #E11D48;
      font-size: 1.15rem;
      margin-bottom: 0.5rem;
    }
    .solution-card {
      background: #ECFDF5;
      border: 1px solid #D1FAE5;
      border-radius: var(--radius);
      padding: 1.75rem;
    }
    .solution-card h4 {
      color: #059669;
      font-size: 1.15rem;
      margin-bottom: 0.5rem;
    }

    /* Product Matrix Cards */
    .product-card {
      background: var(--bg-white);
      border-radius: var(--radius);
      border: 1px solid var(--border-color);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      display: flex;
      flex-direction: column;
    }
    .product-img {
      height: 200px;
      overflow: hidden;
    }
    .product-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      transition: var(--transition);
    }
    .product-card:hover .product-img img {
      transform: scale(1.05);
    }
    .product-body {
      padding: 1.75rem;
      flex: 1;
      display: flex;
      flex-direction: column;
    }
    .product-badge {
      display: inline-block;
      font-size: 0.75rem;
      font-weight: 700;
      color: var(--cyan);
      background: rgba(6, 182, 212, 0.1);
      padding: 2px 8px;
      border-radius: 4px;
      margin-bottom: 0.75rem;
      width: fit-content;
    }
    .product-specs {
      list-style: none;
      margin: 1rem 0 1.5rem 0;
      font-size: 0.9rem;
      color: var(--text-muted);
    }
    .product-specs li {
      margin-bottom: 0.4rem;
      display: flex;
      align-items: center;
      gap: 0.5rem;
    }
    .product-specs li::before {
      content: "✓";
      color: var(--accent);
      font-weight: 800;
    }

    /* Workflow Timeline */
    .workflow-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 1.5rem;
      position: relative;
    }
    .workflow-item {
      background: var(--bg-white);
      border-radius: var(--radius);
      padding: 1.75rem;
      border: 1px solid var(--border-color);
      position: relative;
    }
    .workflow-step {
      font-size: 2rem;
      font-weight: 900;
      color: rgba(16, 185, 129, 0.2);
      line-height: 1;
      margin-bottom: 0.75rem;
      font-family: 'DIN Alternate', Inter, sans-serif;
    }
    .workflow-item h4 {
      font-size: 1.15rem;
      font-weight: 700;
      margin-bottom: 0.5rem;
    }

    /* Metrics Strip */
    .metrics-bar {
      background: linear-gradient(135deg, #0F172A 0%, #1E293B 100%);
      color: #FFFFFF;
      border-radius: var(--radius);
      padding: 3rem 2rem;
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 2rem;
      text-align: center;
    }
    .metric-val {
      font-size: 2.8rem;
      font-weight: 900;
      color: var(--accent);
      font-family: 'DIN Alternate', Inter, sans-serif;
      line-height: 1;
      margin-bottom: 0.5rem;
    }
    .metric-name {
      font-size: 0.95rem;
      color: var(--text-light);
    }

    /* User Stories Split */
    .story-card {
      display: grid;
      grid-template-columns: 1fr 1fr;
      background: var(--bg-white);
      border-radius: var(--radius);
      overflow: hidden;
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-sm);
    }
    .story-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
    }
    .story-body {
      padding: 2.5rem;
      display: flex;
      flex-direction: column;
      justify-content: center;
    }

    /* FAQ Accordion */
    .faq-list {
      display: flex;
      flex-direction: column;
      gap: 1rem;
      max-width: 900px;
      margin: 0 auto;
    }
    .faq-item {
      background: var(--bg-white);
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      overflow: hidden;
    }
    .faq-question {
      padding: 1.25rem 1.5rem;
      font-weight: 700;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      user-select: none;
      font-size: 1.05rem;
    }
    .faq-question:hover {
      color: var(--accent);
    }
    .faq-icon {
      font-size: 1.2rem;
      transition: var(--transition);
      color: var(--text-muted);
    }
    .faq-answer {
      padding: 0 1.5rem 1.25rem 1.5rem;
      color: var(--text-muted);
      font-size: 0.95rem;
      line-height: 1.7;
      display: none;
    }
    .faq-item.active .faq-answer {
      display: block;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
      color: var(--accent);
    }

    /* Lead CTA & Form */
    .cta-container {
      background: radial-gradient(circle at center, #1E293B, #0B0F19);
      border-radius: var(--radius);
      padding: 3.5rem 2.5rem;
      color: #FFFFFF;
      border: 1px solid rgba(255, 255, 255, 0.08);
    }
    .cta-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 3rem;
      align-items: center;
    }
    .lead-form {
      background: var(--bg-white);
      color: var(--text-main);
      padding: 2rem;
      border-radius: var(--radius);
    }
    .form-group {
      margin-bottom: 1.25rem;
    }
    .form-label {
      display: block;
      font-size: 0.85rem;
      font-weight: 700;
      margin-bottom: 0.4rem;
    }
    .form-control {
      width: 100%;
      padding: 0.75rem 1rem;
      border-radius: 6px;
      border: 1px solid var(--border-color);
      font-size: 0.95rem;
      transition: var(--transition);
    }
    .form-control:focus {
      outline: none;
      border-color: var(--accent);
      box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.15);
    }

    /* Footer */
    footer {
      background-color: var(--bg-dark);
      color: var(--text-light);
      padding: 70px 0 25px 0;
      border-top: 1px solid var(--border-dark);
      font-size: 0.9rem;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 3rem;
      margin-bottom: 4rem;
    }
    .footer-col h4 {
      color: #FFFFFF;
      font-size: 1.05rem;
      font-weight: 700;
      margin-bottom: 1.25rem;
    }
    .footer-links {
      list-style: none;
    }
    .footer-links li {
      margin-bottom: 0.6rem;
    }
    .footer-links a:hover {
      color: var(--accent);
    }
    .footer-bottom {
      border-top: 1px solid var(--border-dark);
      padding-top: 1.75rem;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-size: 0.85rem;
      flex-wrap: wrap;
      gap: 1rem;
    }

    /* Responsive */
    @media (max-width: 1024px) {
      .hero-grid, .grid-3, .workflow-grid, .footer-grid, .story-card, .cta-grid {
        grid-template-columns: 1fr;
      }
      .grid-2 {
        grid-template-columns: 1fr;
      }
      .grid-4 {
        grid-template-columns: repeat(2, 1fr);
      }
      .metrics-bar {
        grid-template-columns: repeat(2, 1fr);
      }
      .hero-stage {
        transform: none;
      }
    }

    @media (max-width: 768px) {
      .topbar {
        display: none;
      }
      .navbar-inner {
        height: 60px;
      }
      .nav-links {
        display: none;
      }
      .hero-section {
        padding: 50px 0 60px 0;
      }
      .hero-content h1 {
        font-size: 2.1rem;
      }
      .hero-kpis, .grid-4, .metrics-bar {
        grid-template-columns: 1fr;
      }
      section {
        padding: 55px 0;
      }
      .footer-bottom {
        flex-direction: column;
        align-items: flex-start;
      }
    }