/* roulang page: index */
:root {
      --primary-blue: #1E40AF;
      --primary-light: #3B82F6;
      --accent-green: #10B981;
      --titan-gray: #64748B;
      --dark-slate: #0F172A;
      --card-bg: #FFFFFF;
      --page-bg: #F8FAFC;
      --text-main: #0F172A;
      --text-muted: #475569;
      --text-light: #94A3B8;
      --border-color: rgba(226, 232, 240, 0.8);
      --card-radius: 20px;
      --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
      --shadow-lg: 0 10px 25px -5px rgba(0,0,0,0.04), 0 8px 10px -6px rgba(0,0,0,0.02);
      --shadow-glow: 0 4px 20px rgba(59, 130, 246, 0.35);
      --container-max: 1280px;
    }

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

    body {
      font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Segoe UI", Roboto, sans-serif;
      background-color: var(--page-bg);
      color: var(--text-main);
      line-height: 1.75;
      -webkit-font-smoothing: antialiased;
    }

    a {
      text-decoration: none;
      color: inherit;
      transition: all 0.3s ease;
    }

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

    .container {
      width: 100%;
      max-width: var(--container-max);
      margin-left: auto;
      margin-right: auto;
      padding-left: 24px;
      padding-right: 24px;
    }

    /* Top Bar */
    .top-bar {
      background-color: #0B1329;
      color: #94A3B8;
      font-size: 13px;
      border-bottom: 1px solid rgba(255, 255, 255, 0.08);
      padding: 8px 0;
    }
    .top-bar-inner {
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      gap: 12px;
    }
    .top-bar-links {
      display: flex;
      gap: 20px;
      align-items: center;
    }
    .top-bar-links a:hover {
      color: #FFFFFF;
    }

    /* Header Nav */
    header.site-header {
      background: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(12px);
      position: sticky;
      top: 0;
      z-index: 1000;
      box-shadow: 0 1px 3px rgba(0,0,0,0.05);
      border-bottom: 1px solid rgba(226, 232, 240, 0.8);
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .brand-logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-size: 22px;
      font-weight: 700;
      color: var(--primary-blue);
      letter-spacing: -0.5px;
    }
    .brand-logo i {
      font-size: 26px;
      background: linear-gradient(135deg, var(--primary-blue), var(--primary-light));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }
    .main-nav {
      display: flex;
      align-items: center;
      gap: 28px;
    }
    .nav-link {
      font-size: 15px;
      font-weight: 600;
      color: var(--text-muted);
      position: relative;
      padding: 6px 0;
    }
    .nav-link:hover, .nav-link.active {
      color: var(--primary-blue);
    }
    .nav-link.active::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 100%;
      height: 2px;
      background: linear-gradient(90deg, var(--primary-blue), var(--primary-light));
      border-radius: 2px;
    }

    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      padding: 10px 22px;
      border-radius: 30px;
      font-size: 14px;
      font-weight: 600;
      cursor: pointer;
      transition: all 0.25s ease;
      border: 1px solid transparent;
      text-align: center;
    }
    .btn-primary {
      background: linear-gradient(135deg, var(--primary-blue), var(--primary-light));
      color: #FFFFFF;
      box-shadow: 0 4px 14px 0 rgba(37,99,235,0.39);
    }
    .btn-primary:hover {
      transform: translateY(-2px);
      box-shadow: 0 6px 20px 0 rgba(37,99,235,0.48);
      color: #FFFFFF;
    }
    .btn-primary:active {
      transform: translateY(1px);
    }
    .btn-secondary {
      background: #FFFFFF;
      color: var(--text-main);
      border: 1px solid #CBD5E1;
    }
    .btn-secondary:hover {
      background: #F1F5F9;
      border-color: #94A3B8;
    }
    .btn-outline-white {
      background: transparent;
      color: #FFFFFF;
      border: 1px solid rgba(255, 255, 255, 0.4);
    }
    .btn-outline-white:hover {
      background: rgba(255, 255, 255, 0.1);
      border-color: #FFFFFF;
      color: #FFFFFF;
    }

    /* Badges & Pills */
    .pill-badge {
      display: inline-flex;
      align-items: center;
      gap: 6px;
      padding: 6px 14px;
      border-radius: 9999px;
      font-size: 12px;
      font-weight: 600;
      background: rgba(59, 130, 246, 0.1);
      color: var(--primary-blue);
      border: 1px solid rgba(59, 130, 246, 0.2);
    }
    .pill-badge-green {
      background: rgba(16, 185, 129, 0.1);
      color: var(--accent-green);
      border: 1px solid rgba(16, 185, 129, 0.25);
    }

    /* Section Global */
    section {
      padding: 80px 0;
      position: relative;
    }
    .section-dark {
      background-color: var(--dark-slate);
      color: #FFFFFF;
    }
    .section-white {
      background-color: #FFFFFF;
    }
    .section-header {
      margin-bottom: 48px;
    }
    .section-header.text-center {
      text-align: center;
      max-width: 760px;
      margin-left: auto;
      margin-right: auto;
    }
    .section-title {
      font-size: 32px;
      font-weight: 700;
      letter-spacing: -0.5px;
      margin-top: 12px;
      margin-bottom: 16px;
      color: inherit;
    }
    .section-desc {
      font-size: 16px;
      color: var(--text-muted);
      line-height: 1.8;
    }
    .section-dark .section-desc {
      color: #94A3B8;
    }

    /* Rounded Large Card */
    .card-box {
      background: var(--card-bg);
      border-radius: var(--card-radius);
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-lg);
      padding: 32px;
      transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    }
    .card-box:hover {
      transform: translateY(-4px);
      box-shadow: 0 20px 30px -10px rgba(0,0,0,0.08);
      border-color: rgba(59, 130, 246, 0.4);
    }

    /* Hero Section (API / Dev Blueprint) */
    .hero-section {
      background: linear-gradient(135deg, #091124 0%, #111D3B 50%, #0D1B36 100%);
      color: #FFFFFF;
      padding: 90px 0 100px 0;
      position: relative;
      overflow: hidden;
    }
    .hero-section::before {
      content: '';
      position: absolute;
      top: -150px;
      right: -100px;
      width: 600px;
      height: 600px;
      background: radial-gradient(circle, rgba(59, 130, 246, 0.18) 0%, rgba(0,0,0,0) 70%);
      border-radius: 50%;
      pointer-events: none;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1.15fr 0.85fr;
      gap: 40px;
      align-items: center;
    }
    .hero-title {
      font-size: 42px;
      font-weight: 800;
      line-height: 1.25;
      margin-bottom: 20px;
      letter-spacing: -0.8px;
    }
    .hero-title span {
      background: linear-gradient(135deg, #60A5FA, #34D399);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }
    .hero-intro {
      font-size: 16px;
      color: #CBD5E1;
      margin-bottom: 28px;
      line-height: 1.8;
      max-width: 620px;
    }
    .hero-actions {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
      margin-bottom: 32px;
    }
    .code-mockup {
      background: #040914;
      border: 1px solid rgba(255, 255, 255, 0.12);
      border-radius: 16px;
      box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.7);
      overflow: hidden;
      font-family: "Fira Code", Consolas, Monaco, monospace;
      font-size: 13px;
    }
    .code-header {
      background: #0D162B;
      padding: 12px 18px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    }
    .code-dots {
      display: flex;
      gap: 6px;
    }
    .code-dot {
      width: 10px;
      height: 10px;
      border-radius: 50%;
    }
    .code-dot.red { background: #EF4444; }
    .code-dot.yellow { background: #F59E0B; }
    .code-dot.green { background: #10B981; }
    .code-body {
      padding: 20px;
      color: #E2E8F0;
      line-height: 1.6;
      overflow-x: auto;
    }
    .code-body .c-keyword { color: #F472B6; }
    .code-body .c-func { color: #60A5FA; }
    .code-body .c-str { color: #34D399; }
    .code-body .c-num { color: #FBBF24; }
    .code-body .c-comment { color: #64748B; font-style: italic; }

    /* Section 2: Metrics Board */
    .metrics-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
      margin-top: -50px;
      position: relative;
      z-index: 20;
    }
    .metric-card {
      background: #FFFFFF;
      border-radius: 18px;
      padding: 24px;
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-lg);
      display: flex;
      flex-direction: column;
      justify-content: space-between;
    }
    .metric-val {
      font-size: 34px;
      font-weight: 800;
      color: var(--primary-blue);
      line-height: 1.2;
      margin: 8px 0;
    }
    .metric-title {
      font-size: 14px;
      font-weight: 600;
      color: var(--text-muted);
    }

    /* Section 3: Products Matrix */
    .product-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 30px;
    }
    .product-card {
      overflow: hidden;
      display: flex;
      flex-direction: column;
      height: 100%;
    }
    .product-img-box {
      border-radius: 14px;
      overflow: hidden;
      margin-bottom: 20px;
      background: #EEF2F6;
      position: relative;
      aspect-ratio: 16/10;
    }
    .product-img-box img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      transition: transform 0.5s ease;
    }
    .product-card:hover .product-img-box img {
      transform: scale(1.05);
    }
    .specs-list {
      margin: 16px 0 20px 0;
      padding-top: 16px;
      border-top: 1px dashed var(--border-color);
      list-style: none;
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 10px;
      font-size: 13px;
      color: var(--text-muted);
    }
    .specs-list li i {
      color: var(--accent-green);
      margin-right: 6px;
    }

    /* Section 4: Tech Architecture 6 Grid */
    .grid-6 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .tech-card {
      padding: 28px;
    }
    .tech-icon {
      width: 52px;
      height: 52px;
      border-radius: 12px;
      background: linear-gradient(135deg, rgba(30,64,175,0.08), rgba(59,130,246,0.15));
      color: var(--primary-blue);
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 22px;
      margin-bottom: 18px;
    }

    /* Section 5: Dark Case */
    .dark-case-wrap {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 40px;
      align-items: center;
      background: #1E293B;
      border-radius: 24px;
      padding: 40px;
      border: 1px solid rgba(255, 255, 255, 0.1);
    }
    .dark-case-img {
      border-radius: 16px;
      overflow: hidden;
    }
    .dark-case-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
    }

    /* Section 6: Comparison */
    .compare-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 30px;
    }
    .compare-card {
      padding: 36px;
      border-radius: var(--card-radius);
    }
    .compare-card.traditional {
      background: #F1F5F9;
      border: 1px solid #CBD5E1;
    }
    .compare-card.robotics {
      background: #FFFFFF;
      border: 2px solid var(--primary-light);
      box-shadow: var(--shadow-glow);
      position: relative;
    }
    .compare-item {
      display: flex;
      align-items: flex-start;
      gap: 14px;
      margin-bottom: 20px;
      font-size: 15px;
    }
    .compare-item i {
      font-size: 18px;
      margin-top: 3px;
    }
    .compare-item.bad i { color: #EF4444; }
    .compare-item.good i { color: var(--accent-green); }

    /* Section 7: Stories */
    .story-card {
      display: grid;
      grid-template-columns: 0.9fr 1.1fr;
      gap: 36px;
      align-items: center;
      margin-bottom: 30px;
    }
    .story-card.reverse {
      grid-template-columns: 1.1fr 0.9fr;
    }
    .story-thumb {
      border-radius: 16px;
      overflow: hidden;
      box-shadow: var(--shadow-sm);
    }

    /* Section 8: Milestones */
    .timeline-wrap {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
      position: relative;
      margin-top: 30px;
    }
    .timeline-wrap::before {
      content: '';
      position: absolute;
      top: 30px;
      left: 10%;
      right: 10%;
      height: 2px;
      background: #CBD5E1;
      z-index: 1;
    }
    .timeline-node {
      position: relative;
      z-index: 2;
      background: #FFFFFF;
      padding: 24px 20px;
      border-radius: 16px;
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-sm);
      text-align: center;
    }
    .timeline-dot {
      width: 20px;
      height: 20px;
      border-radius: 50%;
      background: var(--primary-blue);
      border: 4px solid #DBEAFE;
      margin: 0 auto 16px auto;
    }

    /* Section 9: Service Assurance 4 Steps */
    .steps-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
    }
    .step-card {
      position: relative;
      padding: 28px 22px;
      background: #FFFFFF;
      border-radius: 18px;
      border: 1px solid var(--border-color);
    }
    .step-num {
      font-size: 38px;
      font-weight: 800;
      color: rgba(30, 64, 175, 0.12);
      line-height: 1;
      margin-bottom: 12px;
    }

    /* Section 10: News Section */
    .news-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 30px;
    }
    .news-list-item {
      display: flex;
      gap: 16px;
      padding: 16px 0;
      border-bottom: 1px solid #E2E8F0;
    }
    .news-list-item:last-child {
      border-bottom: none;
    }
    .news-date {
      min-width: 70px;
      font-size: 13px;
      color: var(--titan-gray);
      line-height: 1.4;
    }

    /* Section 11: Reviews */
    .reviews-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .review-stars {
      color: #F59E0B;
      margin-bottom: 14px;
      font-size: 14px;
    }
    .client-author {
      display: flex;
      align-items: center;
      gap: 12px;
      margin-top: 20px;
      padding-top: 16px;
      border-top: 1px solid #F1F5F9;
    }
    .author-avatar {
      width: 44px;
      height: 44px;
      border-radius: 50%;
      background: #E2E8F0;
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--primary-blue);
      font-weight: bold;
    }

    /* Section 12: FAQ Accordion */
    .faq-container {
      max-width: 860px;
      margin: 0 auto;
      display: flex;
      flex-direction: column;
      gap: 16px;
    }
    .faq-item {
      background: #FFFFFF;
      border: 1px solid var(--border-color);
      border-radius: 16px;
      overflow: hidden;
      transition: all 0.3s ease;
    }
    .faq-question {
      padding: 22px 26px;
      font-size: 17px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      user-select: none;
    }
    .faq-answer {
      padding: 0 26px 22px 26px;
      color: var(--text-muted);
      font-size: 15px;
      line-height: 1.7;
    }

    /* Section 13: Contact Form CTA */
    .contact-card {
      background: linear-gradient(135deg, #1E40AF 0%, #1E293B 100%);
      color: #FFFFFF;
      border-radius: 24px;
      padding: 48px;
      display: grid;
      grid-template-columns: 1fr 1.1fr;
      gap: 40px;
      align-items: center;
    }
    .form-group {
      margin-bottom: 16px;
    }
    .form-control {
      width: 100%;
      height: 48px;
      border-radius: 10px;
      border: 1px solid rgba(255, 255, 255, 0.2);
      background: rgba(255, 255, 255, 0.95);
      padding: 0 16px;
      font-size: 14px;
      color: #0F172A;
      outline: none;
      transition: border 0.3s, box-shadow 0.3s;
    }
    .form-control:focus {
      border-color: #3B82F6;
      box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.35);
      background: #FFFFFF;
    }
    .form-grid-2 {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 16px;
    }

    /* Footer */
    footer.site-footer {
      background: #0B1329;
      color: #94A3B8;
      padding: 60px 0 24px 0;
      border-top: 1px solid rgba(255, 255, 255, 0.08);
      font-size: 14px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 1.5fr 1fr 1fr 1.2fr;
      gap: 40px;
      margin-bottom: 40px;
    }
    .footer-logo {
      color: #FFFFFF;
      font-size: 20px;
      font-weight: 700;
      margin-bottom: 16px;
      display: inline-block;
    }
    .footer-col h4 {
      color: #FFFFFF;
      font-size: 16px;
      font-weight: 600;
      margin-bottom: 18px;
    }
    .footer-links {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 10px;
    }
    .footer-links a:hover {
      color: #FFFFFF;
    }
    .footer-bottom {
      padding-top: 24px;
      border-top: 1px solid rgba(255, 255, 255, 0.06);
      text-align: center;
      font-size: 13px;
      color: #64748B;
    }

    /* Responsive */
    @media (max-width: 1024px) {
      .hero-grid, .dark-case-wrap, .contact-card {
        grid-template-columns: 1fr;
      }
      .metrics-grid, .product-grid, .grid-6, .timeline-wrap, .steps-grid, .reviews-grid, .footer-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .timeline-wrap::before {
        display: none;
      }
    }
    @media (max-width: 768px) {
      .main-nav {
        display: none;
      }
      .metrics-grid, .product-grid, .grid-6, .compare-grid, .story-card, .story-card.reverse, .timeline-wrap, .steps-grid, .news-grid, .reviews-grid, .footer-grid {
        grid-template-columns: 1fr;
      }
      .hero-title {
        font-size: 28px;
      }
      .section-title {
        font-size: 24px;
      }
      .card-box {
        padding: 20px;
      }
      .contact-card {
        padding: 24px;
      }
      .form-grid-2 {
        grid-template-columns: 1fr;
      }
    }