/* roulang page: index */
:root {
      --bg-dark: #0B0D0F;
      --bg-surface: #111418;
      --bg-light: #F8FAFC;
      --bg-white: #FFFFFF;
      --primary: #111418;
      --accent-green: #00E599;
      --accent-orange: #FF6B00;
      --text-main: #0F172A;
      --text-muted: #64748B;
      --text-light: #E2E8F0;
      --border-light: #E2E8F0;
      --border-dark: rgba(255, 255, 255, 0.08);
      --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      --radius-sm: 4px;
      --radius-md: 8px;
      --radius-full: 9999px;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
      --shadow-card: 0 10px 25px -5px rgba(0, 0, 0, 0.05), 0 8px 10px -6px rgba(0, 0, 0, 0.01);
      --shadow-hover: 0 20px 30px -10px rgba(0, 0, 0, 0.1);
      --transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
    }

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

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

    body {
      font-family: var(--font-sans);
      color: var(--text-main);
      background-color: var(--bg-white);
      line-height: 1.7;
      -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;
      font-size: inherit;
    }

    .container {
      width: 100%;
      max-width: 1240px;
      margin: 0 auto;
      padding: 0 24px;
    }

    .section {
      padding: 88px 0;
      position: relative;
    }

    .section-alt {
      background-color: var(--bg-light);
    }

    .section-dark {
      background-color: var(--bg-dark);
      color: var(--text-light);
    }

    .section-header {
      margin-bottom: 52px;
      max-width: 760px;
    }

    .section-tag {
      display: inline-block;
      font-size: 12px;
      font-weight: 700;
      letter-spacing: 1px;
      text-transform: uppercase;
      color: var(--accent-orange);
      background: rgba(255, 107, 0, 0.08);
      padding: 4px 12px;
      border-radius: var(--radius-sm);
      margin-bottom: 12px;
    }

    .section-dark .section-tag {
      color: var(--accent-green);
      background: rgba(0, 229, 153, 0.1);
    }

    .section-title {
      font-size: 34px;
      font-weight: 700;
      line-height: 1.25;
      letter-spacing: -0.5px;
      margin-bottom: 16px;
    }

    .section-desc {
      font-size: 16px;
      color: var(--text-muted);
      line-height: 1.75;
    }

    .section-dark .section-desc {
      color: #94A3B8;
    }

    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      padding: 12px 24px;
      font-size: 15px;
      font-weight: 600;
      border-radius: var(--radius-sm);
      cursor: pointer;
      border: 1px solid transparent;
      transition: var(--transition);
      line-height: 1;
      height: 48px;
    }

    .btn-primary {
      background-color: var(--primary);
      color: #FFF;
    }

    .btn-primary:hover {
      background-color: #272E36;
      transform: translateY(-2px);
    }

    .btn-accent {
      background-color: var(--accent-orange);
      color: #FFF;
    }

    .btn-accent:hover {
      background-color: #E05E00;
      transform: translateY(-2px);
    }

    .btn-outline {
      border-color: var(--border-light);
      background: #FFF;
      color: var(--text-main);
    }

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

    .btn-ghost-light {
      border-color: rgba(255, 255, 255, 0.2);
      color: #FFF;
      background: transparent;
    }

    .btn-ghost-light:hover {
      background: rgba(255, 255, 255, 0.1);
      border-color: #FFF;
    }

    /* Top bar */
    .topbar {
      height: 36px;
      background-color: #07090A;
      color: #94A3B8;
      font-size: 12px;
      border-bottom: 1px solid rgba(255,255,255,0.06);
    }

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

    .topbar-links {
      display: flex;
      gap: 20px;
    }

    .topbar-contact {
      display: flex;
      gap: 16px;
    }

    /* Main Nav */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 999;
      background-color: rgba(255, 255, 255, 0.96);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border-light);
      height: 72px;
    }

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

    .logo-area {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 800;
      font-size: 20px;
      letter-spacing: -0.5px;
      color: var(--primary);
    }

    .logo-badge {
      width: 32px;
      height: 32px;
      background: var(--primary);
      color: var(--accent-green);
      display: flex;
      align-items: center;
      justify-content: center;
      border-radius: var(--radius-sm);
      font-weight: 900;
      font-size: 15px;
    }

    .nav-menu {
      display: flex;
      align-items: center;
      gap: 28px;
      list-style: none;
    }

    .nav-link {
      font-size: 14px;
      font-weight: 500;
      color: #334155;
      padding: 6px 0;
      position: relative;
    }

    .nav-link:hover, .nav-link.active {
      color: var(--accent-orange);
    }

    .nav-cta {
      display: flex;
      align-items: center;
      gap: 12px;
    }

    .nav-toggle {
      display: none;
      background: none;
      border: none;
      width: 36px;
      height: 36px;
      flex-direction: column;
      justify-content: center;
      gap: 5px;
      cursor: pointer;
    }

    .nav-toggle span {
      display: block;
      width: 22px;
      height: 2px;
      background: var(--primary);
      transition: var(--transition);
    }

    /* Hero */
    .hero-section {
      position: relative;
      background-color: var(--bg-dark);
      color: #FFF;
      min-height: 600px;
      display: flex;
      align-items: center;
      overflow: hidden;
      padding: 100px 0;
    }

    .hero-bg {
      position: absolute;
      inset: 0;
      width: 100%;
      height: 100%;
      object-fit: cover;
      opacity: 0.35;
      filter: saturate(1.1);
    }

    .hero-overlay {
      position: absolute;
      inset: 0;
      background: radial-gradient(circle at 75% 40%, rgba(0, 229, 153, 0.08), transparent 50%),
                  linear-gradient(to right, #0B0D0F 35%, rgba(11, 13, 15, 0.85) 65%, transparent 100%);
    }

    .hero-content {
      position: relative;
      z-index: 2;
      max-width: 680px;
    }

    .hero-h1 {
      font-size: 48px;
      font-weight: 800;
      line-height: 1.15;
      margin-bottom: 24px;
      letter-spacing: -1px;
    }

    .hero-h1 span {
      color: var(--accent-green);
    }

    .hero-desc {
      font-size: 16px;
      line-height: 1.8;
      color: #CBD5E1;
      margin-bottom: 36px;
    }

    .hero-actions {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }

    /* 2. About */
    .about-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 56px;
      align-items: center;
    }

    .about-visual {
      position: relative;
      border-radius: var(--radius-md);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      border: 1px solid var(--border-light);
    }

    .about-badge {
      position: absolute;
      bottom: 24px;
      right: 24px;
      background: rgba(17, 20, 24, 0.95);
      backdrop-filter: blur(8px);
      color: #FFF;
      padding: 16px 20px;
      border-radius: var(--radius-sm);
      border-left: 3px solid var(--accent-green);
      font-size: 13px;
    }

    .about-specs {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 16px;
      margin-top: 28px;
    }

    .spec-item {
      padding: 14px 18px;
      background: var(--bg-light);
      border-radius: var(--radius-sm);
      border: 1px solid var(--border-light);
    }

    .spec-item-num {
      font-size: 20px;
      font-weight: 700;
      color: var(--primary);
      margin-bottom: 4px;
    }

    .spec-item-lbl {
      font-size: 13px;
      color: var(--text-muted);
    }

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

    .feature-card {
      background: #FFF;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 32px 28px;
      transition: var(--transition);
    }

    .feature-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
      border-color: #CBD5E1;
    }

    .feature-icon-bar {
      width: 44px;
      height: 44px;
      background: var(--bg-light);
      border-radius: var(--radius-sm);
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      color: var(--accent-orange);
      margin-bottom: 20px;
      font-size: 18px;
      border: 1px solid var(--border-light);
    }

    .feature-title {
      font-size: 19px;
      font-weight: 700;
      margin-bottom: 12px;
      color: var(--primary);
    }

    .feature-text {
      font-size: 14px;
      color: var(--text-muted);
      line-height: 1.65;
    }

    /* 4. Products */
    .products-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }

    .product-card {
      background: #FFF;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      overflow: hidden;
      display: flex;
      flex-direction: column;
      transition: var(--transition);
    }

    .product-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }

    .product-img-box {
      height: 220px;
      background: var(--bg-light);
      overflow: hidden;
      position: relative;
    }

    .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);
    }

    .product-body {
      padding: 24px;
      flex: 1;
      display: flex;
      flex-direction: column;
    }

    .product-name {
      font-size: 20px;
      font-weight: 700;
      margin-bottom: 8px;
      color: var(--primary);
    }

    .product-subtitle {
      font-size: 13px;
      color: var(--accent-orange);
      font-weight: 600;
      margin-bottom: 14px;
    }

    .product-params {
      list-style: none;
      margin-bottom: 24px;
      font-size: 13px;
      color: #475569;
      border-top: 1px solid var(--border-light);
      padding-top: 14px;
      flex: 1;
    }

    .product-params li {
      display: flex;
      justify-content: space-between;
      padding: 5px 0;
    }

    /* 5. Technology */
    .tech-wrap {
      display: grid;
      grid-template-columns: 1.1fr 0.9fr;
      gap: 56px;
      align-items: center;
    }

    .tech-list {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 20px;
      margin-top: 28px;
    }

    .tech-item {
      background: rgba(255, 255, 255, 0.03);
      border: 1px solid var(--border-dark);
      padding: 20px;
      border-radius: var(--radius-sm);
    }

    .tech-item h4 {
      font-size: 16px;
      color: var(--accent-green);
      margin-bottom: 6px;
    }

    .tech-item p {
      font-size: 14px;
      color: #94A3B8;
      line-height: 1.6;
    }

    .tech-visual-frame {
      border: 1px solid var(--border-dark);
      border-radius: var(--radius-md);
      overflow: hidden;
      background: #000;
    }

    /* 6. Cases */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 32px;
    }

    .case-card {
      background: #FFF;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
    }

    .case-img {
      height: 240px;
      width: 100%;
      object-fit: cover;
    }

    .case-content {
      padding: 28px;
    }

    .case-tag {
      font-size: 12px;
      color: var(--accent-orange);
      font-weight: 700;
      margin-bottom: 8px;
      display: block;
    }

    .case-title {
      font-size: 20px;
      font-weight: 700;
      margin-bottom: 12px;
    }

    .case-desc {
      font-size: 14px;
      color: var(--text-muted);
      line-height: 1.7;
      margin-bottom: 20px;
    }

    .case-stat-badge {
      display: inline-flex;
      align-items: baseline;
      gap: 8px;
      padding: 10px 16px;
      background: var(--bg-light);
      border-radius: var(--radius-sm);
      font-size: 13px;
      font-weight: 600;
    }

    .case-stat-badge b {
      font-size: 20px;
      color: var(--accent-orange);
    }

    /* 7. Statistics */
    .stat-strip {
      background-color: var(--bg-surface);
      border-top: 1px solid var(--border-dark);
      border-bottom: 1px solid var(--border-dark);
      padding: 56px 0;
      color: #FFF;
    }

    .stat-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 32px;
      text-align: center;
    }

    .stat-value {
      font-size: 48px;
      font-weight: 800;
      line-height: 1;
      color: #FFF;
      margin-bottom: 8px;
      font-variant-numeric: tabular-nums;
    }

    .stat-value span {
      font-size: 24px;
      color: var(--accent-green);
    }

    .stat-label {
      font-size: 14px;
      color: #94A3B8;
    }

    /* 8. Testimonials */
    .testi-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }

    .testi-card {
      background: #FFF;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 32px;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
    }

    .testi-quote {
      font-size: 15px;
      color: #334155;
      line-height: 1.75;
      margin-bottom: 24px;
      font-style: normal;
    }

    .testi-author {
      display: flex;
      align-items: center;
      gap: 12px;
      border-top: 1px solid var(--border-light);
      padding-top: 16px;
    }

    .author-avatar {
      width: 44px;
      height: 44px;
      border-radius: var(--radius-full);
      background: #E2E8F0;
      object-fit: cover;
    }

    .author-name {
      font-size: 14px;
      font-weight: 700;
      color: var(--primary);
    }

    .author-unit {
      font-size: 12px;
      color: var(--text-muted);
    }

    /* 9. News */
    .news-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }

    .news-card {
      background: #FFF;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 28px;
      display: flex;
      flex-direction: column;
    }

    .news-date {
      font-size: 12px;
      color: var(--text-muted);
      margin-bottom: 12px;
    }

    .news-heading {
      font-size: 18px;
      font-weight: 700;
      margin-bottom: 12px;
      line-height: 1.4;
      color: var(--primary);
    }

    .news-summary {
      font-size: 14px;
      color: var(--text-muted);
      line-height: 1.65;
      flex: 1;
      margin-bottom: 20px;
    }

    .news-link {
      font-size: 13px;
      font-weight: 600;
      color: var(--accent-orange);
      display: inline-flex;
      align-items: center;
      gap: 4px;
    }

    /* 10. FAQ */
    .faq-container {
      max-width: 860px;
      margin: 0 auto;
    }

    .faq-item {
      border: 1px solid var(--border-light);
      border-radius: var(--radius-sm);
      margin-bottom: 16px;
      background: #FFF;
      overflow: hidden;
    }

    .faq-summary {
      padding: 20px 24px;
      font-size: 16px;
      font-weight: 600;
      cursor: pointer;
      list-style: none;
      display: flex;
      justify-content: space-between;
      align-items: center;
      user-select: none;
    }

    .faq-summary::-webkit-details-marker {
      display: none;
    }

    .faq-summary::after {
      content: "+";
      font-size: 20px;
      font-weight: 400;
      color: var(--text-muted);
      transition: transform 0.2s;
    }

    details[open] .faq-summary::after {
      content: "−";
    }

    .faq-content {
      padding: 0 24px 20px 24px;
      font-size: 14px;
      color: var(--text-muted);
      line-height: 1.75;
      border-top: 1px solid #F1F5F9;
      padding-top: 16px;
    }

    /* 11. Guarantee */
    .guarantee-bar {
      background: #FFF;
      border-top: 1px solid var(--border-light);
      border-bottom: 1px solid var(--border-light);
      padding: 48px 0;
    }

    .guarantee-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 28px;
    }

    .guarantee-item {
      display: flex;
      gap: 16px;
      align-items: flex-start;
    }

    .guarantee-num {
      font-size: 24px;
      font-weight: 800;
      color: var(--accent-orange);
      line-height: 1;
    }

    .guarantee-item h4 {
      font-size: 16px;
      font-weight: 700;
      margin-bottom: 6px;
      color: var(--primary);
    }

    .guarantee-item p {
      font-size: 13px;
      color: var(--text-muted);
      line-height: 1.5;
    }

    /* 12. Contact / CTA */
    .contact-wrapper {
      background: var(--bg-surface);
      border-radius: var(--radius-md);
      padding: 56px;
      color: #FFF;
      display: grid;
      grid-template-columns: 1fr 1.1fr;
      gap: 56px;
    }

    .contact-info h3 {
      font-size: 32px;
      font-weight: 800;
      margin-bottom: 16px;
      line-height: 1.25;
    }

    .contact-info p {
      font-size: 15px;
      color: #94A3B8;
      line-height: 1.7;
      margin-bottom: 32px;
    }

    .contact-list {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 14px;
      font-size: 14px;
      color: #CBD5E1;
    }

    .form-box {
      display: flex;
      flex-direction: column;
      gap: 16px;
    }

    .form-group {
      display: flex;
      flex-direction: column;
      gap: 6px;
    }

    .form-group label {
      font-size: 13px;
      color: #CBD5E1;
    }

    .form-input, .form-select, .form-textarea {
      width: 100%;
      padding: 12px 14px;
      background: rgba(255, 255, 255, 0.05);
      border: 1px solid var(--border-dark);
      border-radius: var(--radius-sm);
      color: #FFF;
      outline: none;
      transition: var(--transition);
    }

    .form-input:focus, .form-select:focus, .form-textarea:focus {
      border-color: var(--accent-green);
      background: rgba(255, 255, 255, 0.08);
    }

    .form-select option {
      background: var(--bg-surface);
      color: #FFF;
    }

    /* Footer */
    .site-footer {
      background: #080A0C;
      color: #94A3B8;
      padding: 72px 0 32px 0;
      border-top: 1px solid var(--border-dark);
      font-size: 13px;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 1.4fr 1fr 1fr 1fr;
      gap: 48px;
      margin-bottom: 56px;
    }

    .footer-brand h4 {
      font-size: 18px;
      color: #FFF;
      font-weight: 800;
      margin-bottom: 14px;
    }

    .footer-col h5 {
      font-size: 15px;
      color: #FFF;
      margin-bottom: 18px;
      font-weight: 600;
    }

    .footer-links {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 10px;
    }

    .footer-links a:hover {
      color: var(--accent-green);
    }

    .footer-bottom {
      border-top: 1px solid rgba(255, 255, 255, 0.06);
      padding-top: 28px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      gap: 16px;
    }

    /* Fixed Bar */
    .float-cta-bar {
      position: fixed;
      bottom: 0;
      left: 0;
      width: 100%;
      background: rgba(17, 20, 24, 0.96);
      backdrop-filter: blur(10px);
      border-top: 1px solid var(--border-dark);
      padding: 12px 24px;
      z-index: 990;
      display: flex;
      justify-content: space-between;
      align-items: center;
      box-shadow: 0 -4px 20px rgba(0,0,0,0.25);
    }

    .float-cta-info {
      color: #FFF;
      font-size: 14px;
      display: flex;
      align-items: center;
      gap: 12px;
    }

    .float-dot {
      width: 8px;
      height: 8px;
      border-radius: 50%;
      background-color: var(--accent-green);
      box-shadow: 0 0 8px var(--accent-green);
    }

    .float-cta-actions {
      display: flex;
      gap: 12px;
    }

    /* Responsive */
    @media (max-width: 1024px) {
      .features-grid, .products-grid, .testi-grid, .news-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .guarantee-grid, .stat-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .about-grid, .tech-wrap, .contact-wrapper {
        grid-template-columns: 1fr;
        gap: 40px;
      }
      .footer-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .hero-h1 {
        font-size: 38px;
      }
    }

    @media (max-width: 768px) {
      .topbar {
        display: none;
      }
      .nav-menu {
        position: fixed;
        top: 72px;
        left: 0;
        width: 100%;
        background: #FFF;
        flex-direction: column;
        padding: 24px;
        box-shadow: var(--shadow-hover);
        border-bottom: 1px solid var(--border-light);
        display: none;
      }
      .nav-menu.open {
        display: flex;
      }
      .nav-cta {
        display: none;
      }
      .nav-toggle {
        display: flex;
      }
      .hero-section {
        min-height: auto;
        padding: 60px 0;
      }
      .hero-h1 {
        font-size: 32px;
      }
      .section {
        padding: 56px 0;
      }
      .section-title {
        font-size: 26px;
      }
      .features-grid, .products-grid, .cases-grid, .testi-grid, .news-grid, .guarantee-grid, .stat-grid {
        grid-template-columns: 1fr;
      }
      .contact-wrapper {
        padding: 28px 20px;
      }
      .footer-grid {
        grid-template-columns: 1fr;
      }
      .float-cta-info {
        display: none;
      }
      .float-cta-bar {
        justify-content: center;
      }
      .float-cta-actions {
        width: 100%;
      }
      .float-cta-actions .btn {
        flex: 1;
      }
    }

    @media (max-width: 375px) {
      .hero-h1 {
        font-size: 28px;
      }
      .btn {
        padding: 10px 16px;
        font-size: 14px;
      }
    }