/* roulang page: index */
:root {
      --bg-base: #0A0B0E;
      --bg-darker: #050507;
      --bg-card: #13151B;
      --bg-card-hover: #1B1E26;
      --primary: #00F5A0;
      --primary-dim: rgba(0, 245, 160, 0.12);
      --primary-border: rgba(0, 245, 160, 0.35);
      --accent: #7B2CBF;
      --accent-glow: #9D4EDD;
      --text-main: #FFFFFF;
      --text-body: #C4C7D4;
      --text-muted: #7A7F96;
      --border-line: rgba(255, 255, 255, 0.08);
      --radius-sm: 6px;
      --radius-md: 12px;
      --radius-pill: 9999px;
      --container: 1200px;
      --font-stack: system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Segoe UI", Roboto, sans-serif;
      --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    }

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

    html {
      scroll-behavior: smooth;
      background-color: var(--bg-base);
      color: var(--text-body);
      font-family: var(--font-stack);
      -webkit-font-smoothing: antialiased;
    }

    body {
      overflow-x: hidden;
      line-height: 1.65;
      font-size: 15px;
    }

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

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

    button, input {
      font-family: inherit;
    }

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

    /* Top Bar */
    .top-bar {
      background: #0d0f14;
      border-bottom: 1px solid var(--border-line);
      font-size: 12px;
      color: var(--text-muted);
      padding: 8px 0;
    }
    .top-bar-inner {
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .top-bar-left {
      display: flex;
      gap: 20px;
      align-items: center;
    }
    .status-dot {
      display: inline-block;
      width: 7px;
      height: 7px;
      border-radius: 50%;
      background: var(--primary);
      box-shadow: 0 0 8px var(--primary);
      margin-right: 6px;
    }

    /* Header Nav */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 1000;
      background: rgba(10, 11, 14, 0.82);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border-line);
      transition: var(--transition-smooth);
    }
    .nav-container {
      height: 70px;
      display: flex;
      align-items: center;
      justify-content: space-between;
    }
    .nav-brand {
      display: flex;
      align-items: center;
      gap: 10px;
      font-size: 20px;
      font-weight: 800;
      color: var(--text-main);
      letter-spacing: -0.5px;
    }
    .nav-brand span {
      color: var(--primary);
    }
    .nav-menu {
      display: flex;
      align-items: center;
      list-style: none;
      gap: 28px;
    }
    .nav-link {
      font-size: 14px;
      font-weight: 500;
      color: var(--text-body);
    }
    .nav-link:hover, .nav-link.active {
      color: var(--primary);
    }
    .nav-cta {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      background: var(--primary);
      color: #050507;
      font-weight: 700;
      font-size: 13px;
      padding: 9px 20px;
      border-radius: var(--radius-sm);
      border: 1px solid var(--primary);
      cursor: pointer;
      box-shadow: 0 2px 10px rgba(0, 245, 160, 0.2);
    }
    .nav-cta:hover {
      transform: translateY(-2px);
      box-shadow: 0 8px 24px rgba(0, 245, 160, 0.35);
      background: #15ffac;
    }
    .mobile-menu-toggle {
      display: none;
      background: transparent;
      border: 1px solid var(--border-line);
      color: var(--text-main);
      padding: 6px 12px;
      border-radius: var(--radius-sm);
      cursor: pointer;
      font-size: 14px;
    }

    /* Section Global */
    section {
      padding: 90px 0;
      position: relative;
      border-bottom: 1px solid var(--border-line);
    }
    .section-alt {
      background-color: var(--bg-darker);
    }
    .section-header {
      margin-bottom: 48px;
      max-width: 800px;
    }
    .section-tag {
      display: inline-flex;
      align-items: center;
      gap: 6px;
      padding: 4px 12px;
      border-radius: var(--radius-pill);
      background: var(--primary-dim);
      border: 1px solid var(--primary-border);
      color: var(--primary);
      font-size: 12px;
      font-weight: 600;
      margin-bottom: 16px;
      text-transform: uppercase;
    }
    .section-title {
      font-size: 32px;
      font-weight: 700;
      color: var(--text-main);
      line-height: 1.25;
      letter-spacing: -0.5px;
      margin-bottom: 16px;
    }
    .section-subtitle {
      font-size: 15px;
      color: var(--text-body);
      line-height: 1.7;
    }

    /* Hero Banner: Blueprint D Full-width Banner */
    .hero-strip {
      padding: 70px 0 60px;
      background: linear-gradient(180deg, rgba(19, 21, 27, 0.9) 0%, rgba(10, 11, 14, 0.98) 100%), url('/assets/images/backpic/back-1.png') center/cover no-repeat;
      position: relative;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1.2fr 0.8fr;
      gap: 40px;
      align-items: center;
    }
    .hero-h1 {
      font-size: 46px;
      font-weight: 800;
      color: var(--text-main);
      line-height: 1.18;
      margin-bottom: 20px;
    }
    .hero-h1 em {
      font-style: normal;
      color: var(--primary);
    }
    .hero-desc {
      font-size: 16px;
      color: var(--text-body);
      line-height: 1.75;
      margin-bottom: 32px;
    }
    .hero-actions {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn-main {
      background: var(--primary);
      color: #050507;
      font-size: 15px;
      font-weight: 700;
      padding: 13px 28px;
      border-radius: var(--radius-sm);
      display: inline-flex;
      align-items: center;
      gap: 8px;
      box-shadow: 0 4px 18px rgba(0, 245, 160, 0.25);
    }
    .btn-main:hover {
      transform: translateY(-2px);
      box-shadow: 0 8px 26px rgba(0, 245, 160, 0.4);
    }
    .btn-secondary {
      background: var(--bg-card);
      border: 1px solid var(--border-line);
      color: var(--text-main);
      font-size: 15px;
      font-weight: 600;
      padding: 13px 26px;
      border-radius: var(--radius-sm);
    }
    .btn-secondary:hover {
      border-color: rgba(255, 255, 255, 0.25);
      background: var(--bg-card-hover);
    }
    .hero-showcase {
      border: 1px solid var(--border-line);
      border-radius: var(--radius-md);
      overflow: hidden;
      background: var(--bg-card);
      box-shadow: 0 16px 40px rgba(0,0,0,0.6);
      position: relative;
    }
    .hero-showcase-badge {
      position: absolute;
      top: 14px;
      right: 14px;
      background: rgba(5, 5, 7, 0.85);
      backdrop-filter: blur(8px);
      border: 1px solid var(--primary-border);
      color: var(--primary);
      font-size: 11px;
      padding: 4px 10px;
      border-radius: 4px;
      font-weight: 600;
    }

    /* Section 2: Technical Spec & Architecture */
    .spec-split {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .spec-details-list {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 16px;
      margin-top: 24px;
    }
    .spec-details-item {
      display: flex;
      align-items: flex-start;
      gap: 12px;
      padding: 14px;
      background: var(--bg-card);
      border: 1px solid var(--border-line);
      border-radius: var(--radius-sm);
    }
    .spec-icon {
      color: var(--primary);
      font-size: 18px;
      line-height: 1;
      margin-top: 3px;
    }
    .spec-image-box {
      border-radius: var(--radius-md);
      border: 1px solid var(--border-line);
      overflow: hidden;
      background: var(--bg-card);
    }

    /* Section 3: 6 Card Core Advantages */
    .grid-3x2 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .adv-card {
      background: var(--bg-card);
      border: 1px solid var(--border-line);
      border-radius: var(--radius-md);
      padding: 30px 24px;
      position: relative;
      transition: var(--transition-smooth);
    }
    .adv-card:hover {
      border-color: var(--primary-border);
      transform: translateY(-4px);
      box-shadow: 0 10px 30px rgba(0,0,0,0.5);
    }
    .adv-index {
      font-size: 12px;
      font-weight: 700;
      color: var(--primary);
      margin-bottom: 12px;
      letter-spacing: 1px;
    }
    .adv-title {
      font-size: 18px;
      font-weight: 700;
      color: var(--text-main);
      margin-bottom: 10px;
    }
    .adv-text {
      font-size: 14px;
      color: var(--text-body);
      line-height: 1.6;
    }

    /* Section 4: 3 Asset Style Packs */
    .grid-3-col {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .product-asset-card {
      background: var(--bg-card);
      border: 1px solid var(--border-line);
      border-radius: var(--radius-md);
      overflow: hidden;
      display: flex;
      flex-direction: column;
      transition: var(--transition-smooth);
    }
    .product-asset-card:hover {
      border-color: rgba(255, 255, 255, 0.25);
    }
    .asset-card-thumb {
      height: 220px;
      overflow: hidden;
    }
    .asset-card-thumb img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      transition: transform 0.5s ease;
    }
    .product-asset-card:hover .asset-card-thumb img {
      transform: scale(1.05);
    }
    .asset-card-body {
      padding: 24px;
      flex: 1;
      display: flex;
      flex-direction: column;
    }
    .asset-title {
      font-size: 20px;
      color: var(--text-main);
      font-weight: 700;
      margin-bottom: 10px;
    }
    .asset-desc {
      font-size: 14px;
      color: var(--text-body);
      line-height: 1.6;
      margin-bottom: 20px;
      flex: 1;
    }
    .asset-link {
      font-size: 13px;
      font-weight: 600;
      color: var(--primary);
      display: inline-flex;
      align-items: center;
      gap: 6px;
    }

    /* Section 5: Engineering Contrast Plate */
    .compare-container {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 32px;
    }
    .compare-box {
      background: var(--bg-card);
      border: 1px solid var(--border-line);
      border-radius: var(--radius-md);
      padding: 36px 30px;
    }
    .compare-box.active {
      border-color: var(--primary-border);
      background: #0f131a;
      box-shadow: 0 0 30px rgba(0, 245, 160, 0.05);
    }
    .compare-header {
      display: flex;
      justify-content: space-between;
      align-items: center;
      margin-bottom: 24px;
      padding-bottom: 16px;
      border-bottom: 1px solid var(--border-line);
    }
    .compare-title {
      font-size: 18px;
      font-weight: 700;
      color: var(--text-main);
    }
    .compare-pill {
      font-size: 12px;
      font-weight: 600;
      padding: 3px 10px;
      border-radius: var(--radius-pill);
    }
    .pill-muted {
      background: rgba(255,255,255,0.06);
      color: var(--text-muted);
    }
    .pill-green {
      background: var(--primary-dim);
      color: var(--primary);
      border: 1px solid var(--primary-border);
    }
    .compare-list {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 16px;
      font-size: 14px;
    }
    .compare-list li {
      display: flex;
      justify-content: space-between;
      color: var(--text-body);
    }
    .compare-list strong {
      color: var(--text-main);
    }

    /* Section 6: User Story Cards */
    .story-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 32px;
    }
    .story-card {
      background: var(--bg-card);
      border: 1px solid var(--border-line);
      border-radius: var(--radius-md);
      overflow: hidden;
      display: flex;
      flex-direction: column;
    }
    .story-card-content {
      padding: 32px;
    }
    .story-badge {
      font-size: 12px;
      color: var(--primary);
      font-weight: 600;
      margin-bottom: 12px;
    }
    .story-headline {
      font-size: 20px;
      font-weight: 700;
      color: var(--text-main);
      margin-bottom: 14px;
      line-height: 1.35;
    }
    .story-text {
      font-size: 14px;
      color: var(--text-body);
      line-height: 1.65;
      margin-bottom: 20px;
    }
    .story-stats-row {
      display: flex;
      gap: 24px;
      padding-top: 16px;
      border-top: 1px solid var(--border-line);
    }
    .story-stat-val {
      font-size: 20px;
      font-weight: 800;
      color: var(--primary);
    }
    .story-stat-lbl {
      font-size: 12px;
      color: var(--text-muted);
    }

    /* Section 7: Metric Strip */
    .metric-strip-wrapper {
      background: #060709;
      border: 1px solid var(--border-line);
      border-radius: var(--radius-md);
      padding: 40px 20px;
    }
    .metric-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      text-align: center;
      gap: 20px;
    }
    .metric-item {
      padding: 0 16px;
      border-right: 1px solid var(--border-line);
    }
    .metric-item:last-child {
      border-right: none;
    }
    .metric-num {
      font-size: 42px;
      font-weight: 800;
      color: var(--text-main);
      line-height: 1.1;
      margin-bottom: 8px;
    }
    .metric-num span {
      color: var(--primary);
    }
    .metric-label {
      font-size: 13px;
      color: var(--text-muted);
      font-weight: 500;
    }

    /* Section 8: 4-Step Technical Decomposition */
    .step-flow {
      display: flex;
      flex-direction: column;
      gap: 24px;
    }
    .step-row {
      display: grid;
      grid-template-columns: 80px 1fr 1.2fr;
      gap: 24px;
      align-items: center;
      padding: 24px;
      background: var(--bg-card);
      border: 1px solid var(--border-line);
      border-radius: var(--radius-md);
    }
    .step-number {
      font-size: 28px;
      font-weight: 800;
      color: var(--primary);
      text-align: center;
    }
    .step-info h3 {
      font-size: 18px;
      color: var(--text-main);
      margin-bottom: 8px;
    }
    .step-info p {
      font-size: 14px;
      color: var(--text-muted);
      line-height: 1.55;
    }
    .step-meta {
      font-size: 13px;
      color: var(--text-body);
      background: rgba(0,0,0,0.3);
      padding: 14px 18px;
      border-radius: var(--radius-sm);
      border-left: 2px solid var(--primary);
    }

    /* Section 9: 4-Column Adaptation Matrix */
    .matrix-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
    }
    .matrix-card {
      background: var(--bg-card);
      border: 1px solid var(--border-line);
      border-radius: var(--radius-md);
      padding: 24px 20px;
      transition: var(--transition-smooth);
    }
    .matrix-card:hover {
      border-color: rgba(255, 255, 255, 0.2);
    }
    .matrix-tag {
      font-size: 11px;
      color: var(--primary);
      font-weight: 700;
      margin-bottom: 8px;
    }
    .matrix-title {
      font-size: 17px;
      color: var(--text-main);
      font-weight: 700;
      margin-bottom: 12px;
    }
    .matrix-desc {
      font-size: 13px;
      color: var(--text-body);
      line-height: 1.6;
    }

    /* Section 10: Testimonials Wall */
    .testimonial-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .testi-card {
      background: var(--bg-card);
      border: 1px solid var(--border-line);
      border-radius: var(--radius-md);
      padding: 28px 24px;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
    }
    .testi-stars {
      color: #FFB703;
      margin-bottom: 14px;
      font-size: 14px;
      letter-spacing: 2px;
    }
    .testi-text {
      font-size: 14px;
      color: var(--text-body);
      line-height: 1.65;
      margin-bottom: 20px;
      font-style: italic;
    }
    .testi-author {
      display: flex;
      align-items: center;
      gap: 12px;
    }
    .testi-avatar-placeholder {
      width: 42px;
      height: 42px;
      border-radius: 50%;
      background: #252833;
      border: 1px solid var(--border-line);
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--primary);
      font-weight: 700;
      font-size: 14px;
    }
    .testi-name {
      font-size: 14px;
      font-weight: 700;
      color: var(--text-main);
    }
    .testi-role {
      font-size: 12px;
      color: var(--text-muted);
    }

    /* Section 11: News & Tech Weekly */
    .news-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
      margin-bottom: 32px;
    }
    .news-card {
      background: var(--bg-card);
      border: 1px solid var(--border-line);
      border-radius: var(--radius-md);
      overflow: hidden;
      padding: 24px;
      display: flex;
      flex-direction: column;
      transition: var(--transition-smooth);
    }
    .news-card:hover {
      border-color: rgba(255, 255, 255, 0.2);
    }
    .news-date {
      font-size: 12px;
      color: var(--text-muted);
      margin-bottom: 8px;
    }
    .news-title {
      font-size: 16px;
      font-weight: 700;
      color: var(--text-main);
      margin-bottom: 12px;
      line-height: 1.4;
    }
    .news-summary {
      font-size: 13px;
      color: var(--text-body);
      line-height: 1.6;
    }

    /* Section 12: FAQ Accordion */
    .faq-list {
      max-width: 860px;
      margin: 0 auto;
      display: flex;
      flex-direction: column;
      gap: 16px;
    }
    .faq-item {
      background: var(--bg-card);
      border: 1px solid var(--border-line);
      border-radius: var(--radius-md);
      overflow: hidden;
    }
    .faq-trigger {
      width: 100%;
      padding: 20px 24px;
      background: none;
      border: none;
      text-align: left;
      color: var(--text-main);
      font-size: 16px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
    }
    .faq-trigger span:last-child {
      color: var(--primary);
      font-size: 20px;
      transition: transform 0.3s;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease, padding 0.35s ease;
      background: #0f1116;
      color: var(--text-body);
      font-size: 14px;
      line-height: 1.7;
    }
    .faq-item.active .faq-answer {
      max-height: 220px;
      padding: 0 24px 20px;
    }
    .faq-item.active .faq-trigger span:last-child {
      transform: rotate(45deg);
    }

    /* Section 13: Final Conversion CTA */
    .cta-card-wrapper {
      background: radial-gradient(circle at center, #1b2820 0%, #0d0f14 100%);
      border: 1px solid var(--primary-border);
      border-radius: var(--radius-md);
      padding: 60px 40px;
      text-align:center;
      position: relative;
      box-shadow: 0 20px 50px rgba(0, 245, 160, 0.08);
    }
    .cta-card-wrapper h2 {
      font-size: 34px;
      font-weight: 800;
      color: var(--text-main);
      margin-bottom: 16px;
    }
    .cta-card-wrapper p {
      font-size: 16px;
      color: var(--text-body);
      max-width: 640px;
      margin: 0 auto 32px;
      line-height: 1.7;
    }
    .cta-form-single {
      max-width: 520px;
      margin: 0 auto;
      display: flex;
      gap: 12px;
    }
    .cta-input {
      flex: 1;
      background: #08090b;
      border: 1px solid var(--border-line);
      border-radius: var(--radius-sm);
      padding: 14px 18px;
      color: var(--text-main);
      font-size: 14px;
      outline: none;
    }
    .cta-input:focus {
      border-color: var(--primary);
      box-shadow: 0 0 12px rgba(0, 245, 160, 0.2);
    }

    /* Footer */
    .site-footer {
      background: #060709;
      border-top: 1px solid var(--border-line);
      padding: 70px 0 30px;
      font-size: 13px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 1.5fr 1fr 1fr 1.2fr;
      gap: 40px;
      margin-bottom: 50px;
    }
    .footer-col h4 {
      font-size: 15px;
      font-weight: 700;
      color: var(--text-main);
      margin-bottom: 18px;
    }
    .footer-col p {
      color: var(--text-muted);
      line-height: 1.7;
      margin-bottom: 14px;
    }
    .footer-links {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 10px;
    }
    .footer-links a {
      color: var(--text-muted);
    }
    .footer-links a:hover {
      color: var(--primary);
    }
    .footer-bottom {
      border-top: 1px solid var(--border-line);
      padding-top: 24px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      color: var(--text-muted);
      font-size: 12px;
      flex-wrap: wrap;
      gap: 12px;
    }
    .footer-bottom-links {
      display: flex;
      gap: 20px;
    }

    /* Responsive Breakpoints */
    @media (max-width: 1024px) {
      .hero-grid {
        grid-template-columns: 1fr;
        gap: 32px;
      }
      .grid-3x2, .grid-3-col, .testimonial-grid, .news-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .matrix-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .metric-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 24px;
      }
      .metric-item:nth-child(2) {
        border-right: none;
      }
      .footer-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }

    @media (max-width: 768px) {
      section {
        padding: 56px 0;
      }
      .hero-h1 {
        font-size: 32px;
      }
      .spec-split, .compare-container, .story-grid {
        grid-template-columns: 1fr;
      }
      .step-row {
        grid-template-columns: 1fr;
        gap: 12px;
      }
      .grid-3x2, .grid-3-col, .testimonial-grid, .news-grid, .matrix-grid {
        grid-template-columns: 1fr;
      }
      .cta-form-single {
        flex-direction: column;
      }
      .nav-menu {
        display: none;
        position: absolute;
        top: 70px;
        left: 0;
        width: 100%;
        background: #0d0f14;
        flex-direction: column;
        padding: 24px;
        border-bottom: 1px solid var(--border-line);
        gap: 18px;
      }
      .nav-menu.show {
        display: flex;
      }
      .mobile-menu-toggle {
        display: block;
      }
      .metric-grid {
        grid-template-columns: 1fr;
      }
      .metric-item {
        border-right: none;
        border-bottom: 1px solid var(--border-line);
        padding-bottom: 16px;
      }
      .metric-item:last-child {
        border-bottom: none;
      }
      .footer-grid {
        grid-template-columns: 1fr;
      }
      .footer-bottom {
        flex-direction: column;
        align-items: flex-start;
      }
    }