/* roulang page: index */
:root {
      --bg-primary: #F8F9FA;
      --bg-surface: #FFFFFF;
      --bg-dark: #0F1115;
      --bg-dark-card: #171A21;
      --text-main: #14171A;
      --text-secondary: #4A5568;
      --text-muted: #718096;
      --text-light: #E2E8F0;
      --brand-green: #00875A;
      --brand-green-light: #E3FCEF;
      --brand-green-hover: #006644;
      --accent-blue: #2C5282;
      --border-light: #E2E8F0;
      --border-dark: #2D3748;
      --danger-red: #C53030;
      --font-base: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      --font-mono: 'Fira Code', 'Roboto Mono', monospace;
      --radius-sm: 4px;
      --radius-md: 8px;
      --radius-lg: 12px;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.05);
      --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.05), 0 2px 4px -1px rgba(0,0,0,0.03);
      --shadow-lg: 0 10px 25px -5px rgba(0, 0, 0, 0.05);
      --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    }

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

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

    body {
      background-color: var(--bg-primary);
      color: var(--text-main);
      font-family: var(--font-base);
      line-height: 1.65;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }

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

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

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

    /* Top Utility Bar */
    .top-bar {
      background-color: var(--bg-dark);
      color: #A0AEC0;
      font-size: 12px;
      height: 38px;
      display: flex;
      align-items: center;
      border-bottom: 1px solid #1A202C;
    }
    .top-bar .container {
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .status-badge {
      display: inline-flex;
      align-items: center;
      gap: 8px;
    }
    .status-dot {
      width: 7px;
      height: 7px;
      background-color: #38A169;
      border-radius: 50%;
      box-shadow: 0 0 8px #38A169;
      animation: pulse 2s infinite;
    }
    @keyframes pulse {
      0% { opacity: 0.6; }
      50% { opacity: 1; }
      100% { opacity: 0.6; }
    }
    .top-info {
      display: flex;
      align-items: center;
      gap: 20px;
    }

    /* Main Navigation */
    .site-header {
      background: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(8px);
      border-bottom: 1px solid var(--border-light);
      position: sticky;
      top: 0;
      z-index: 1000;
      transition: var(--transition);
    }
    .nav-wrapper {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .brand-logo {
      display: flex;
      align-items: center;
      gap: 12px;
      font-size: 20px;
      font-weight: 700;
      color: var(--text-main);
      letter-spacing: -0.02em;
    }
    .brand-logo-icon {
      width: 32px;
      height: 32px;
      background: var(--brand-green);
      color: #fff;
      display: flex;
      align-items: center;
      justify-content: center;
      border-radius: var(--radius-sm);
      font-size: 16px;
    }
    .nav-menu {
      display: flex;
      align-items: center;
      list-style: none;
      gap: 28px;
    }
    .nav-link {
      font-size: 14px;
      font-weight: 500;
      color: var(--text-secondary);
      position: relative;
      padding: 6px 0;
    }
    .nav-link:hover, .nav-link.active {
      color: var(--brand-green);
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background-color: var(--brand-green);
      transition: var(--transition);
    }
    .nav-link:hover::after, .nav-link.active::after {
      width: 100%;
    }
    .nav-actions {
      display: flex;
      align-items: center;
      gap: 12px;
    }

    /* Buttons */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 9px 18px;
      font-size: 14px;
      font-weight: 600;
      border-radius: var(--radius-sm);
      cursor: pointer;
      border: 1px solid transparent;
      transition: var(--transition);
      gap: 8px;
    }
    .btn-primary {
      background-color: var(--brand-green);
      color: #FFFFFF;
    }
    .btn-primary:hover {
      background-color: var(--brand-green-hover);
      transform: translateY(-1px);
    }
    .btn-outline {
      border-color: var(--border-light);
      background-color: #FFFFFF;
      color: var(--text-main);
    }
    .btn-outline:hover {
      border-color: var(--text-main);
      background-color: var(--bg-primary);
    }
    .btn-dark {
      background-color: var(--bg-dark);
      color: #FFFFFF;
    }
    .btn-dark:hover {
      background-color: #2D3748;
    }

    /* Section Base */
    .section {
      padding: 80px 0;
      position: relative;
    }
    .section-white {
      background-color: var(--bg-surface);
    }
    .section-gray {
      background-color: var(--bg-primary);
      border-top: 1px solid var(--border-light);
      border-bottom: 1px solid var(--border-light);
    }
    .section-dark {
      background-color: var(--bg-dark);
      color: #FFFFFF;
    }
    .section-header {
      margin-bottom: 48px;
    }
    .section-header.text-center {
      text-align: center;
      max-width: 800px;
      margin-left: auto;
      margin-right: auto;
    }
    .section-tag {
      display: inline-block;
      font-size: 12px;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.08em;
      color: var(--brand-green);
      margin-bottom: 8px;
    }
    .section-dark .section-tag {
      color: #48BB78;
    }
    .section-title {
      font-size: 32px;
      font-weight: 700;
      line-height: 1.25;
      color: inherit;
      margin-bottom: 14px;
    }
    .section-desc {
      font-size: 15px;
      color: var(--text-secondary);
      line-height: 1.7;
    }
    .section-dark .section-desc {
      color: #A0AEC0;
    }

    /* Section 1: Hero (Help & Knowledge Base Style) */
    .hero-section {
      position: relative;
      padding: 90px 0 80px;
      background: radial-gradient(circle at 50% 20%, #FFFFFF 0%, #F0F4F8 100%);
      border-bottom: 1px solid var(--border-light);
      overflow: hidden;
    }
    .hero-bg-media {
      position: absolute;
      top: 0;
      right: 0;
      width: 100%;
      height: 100%;
      object-fit: cover;
      opacity: 0.04;
      pointer-events: none;
    }
    .hero-content {
      position: relative;
      z-index: 2;
      max-width: 860px;
      margin: 0 auto;
      text-align: center;
    }
    .hero-h1 {
      font-size: 46px;
      font-weight: 800;
      letter-spacing: -0.03em;
      line-height: 1.2;
      margin-bottom: 20px;
      color: var(--text-main);
    }
    .hero-p {
      font-size: 16px;
      color: var(--text-secondary);
      line-height: 1.8;
      margin-bottom: 36px;
    }
    .search-box {
      background: #FFFFFF;
      border: 1px solid var(--border-light);
      box-shadow: 0 12px 30px rgba(0,0,0,0.06);
      border-radius: var(--radius-md);
      padding: 8px 10px 8px 20px;
      display: flex;
      align-items: center;
      gap: 12px;
      max-width: 680px;
      margin: 0 auto 20px;
    }
    .search-input {
      flex: 1;
      border: none;
      outline: none;
      font-size: 15px;
      color: var(--text-main);
    }
    .chips-group {
      display: flex;
      flex-wrap: wrap;
      align-items: center;
      justify-content: center;
      gap: 8px;
    }
    .chip-item {
      font-size: 12px;
      padding: 5px 12px;
      background: #FFFFFF;
      border: 1px solid var(--border-light);
      border-radius: 20px;
      color: var(--text-secondary);
      display: inline-flex;
      align-items: center;
      gap: 6px;
    }
    .chip-item:hover {
      border-color: var(--brand-green);
      color: var(--brand-green);
    }

    /* Section 2: Brand Story */
    .story-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 50px;
      align-items: center;
    }
    .story-img-wrap {
      border-radius: var(--radius-lg);
      overflow: hidden;
      border: 1px solid var(--border-light);
      position: relative;
    }
    .story-img {
      width: 100%;
      height: 380px;
      object-fit: cover;
    }
    .story-stats {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 20px;
      margin-top: 30px;
    }
    .story-stat-card {
      padding: 16px;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      background: #FAFAFA;
    }
    .stat-val {
      font-size: 26px;
      font-weight: 700;
      color: var(--brand-green);
      font-family: var(--font-mono);
    }
    .stat-label {
      font-size: 13px;
      color: var(--text-muted);
    }

    /* Section 3: Series Nav */
    .series-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
    }
    .series-card {
      background: #FFFFFF;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 24px;
      transition: var(--transition);
      display: flex;
      flex-direction: column;
      justify-content: space-between;
    }
    .series-card:hover {
      border-color: var(--brand-green);
      box-shadow: var(--shadow-lg);
      transform: translateY(-3px);
    }
    .series-icon {
      font-size: 24px;
      color: var(--brand-green);
      margin-bottom: 16px;
    }
    .series-card h3 {
      font-size: 18px;
      font-weight: 600;
      margin-bottom: 10px;
    }
    .series-card p {
      font-size: 14px;
      color: var(--text-secondary);
      line-height: 1.6;
      margin-bottom: 16px;
    }
    .series-link {
      font-size: 13px;
      font-weight: 600;
      color: var(--brand-green);
      display: inline-flex;
      align-items: center;
      gap: 6px;
    }

    /* Section 4: Hot Grid */
    .hot-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .hot-card {
      background: #FFFFFF;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      overflow: hidden;
      transition: var(--transition);
    }
    .hot-card:hover {
      box-shadow: var(--shadow-lg);
      border-color: #CBD5E0;
    }
    .hot-thumb {
      height: 180px;
      position: relative;
      overflow: hidden;
    }
    .hot-thumb img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      transition: var(--transition);
    }
    .hot-card:hover .hot-thumb img {
      transform: scale(1.04);
    }
    .hot-badge {
      position: absolute;
      top: 12px;
      right: 12px;
      background: rgba(15, 17, 21, 0.85);
      color: #FFFFFF;
      font-size: 11px;
      padding: 4px 10px;
      border-radius: var(--radius-sm);
      font-family: var(--font-mono);
    }
    .hot-body {
      padding: 20px;
    }
    .hot-body h4 {
      font-size: 17px;
      font-weight: 600;
      margin-bottom: 8px;
    }
    .hot-body p {
      font-size: 14px;
      color: var(--text-secondary);
      line-height: 1.6;
      margin-bottom: 16px;
    }
    .hot-meta {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding-top: 12px;
      border-top: 1px solid var(--border-light);
      font-size: 12px;
      color: var(--text-muted);
    }

    /* Section 5: Member Rights */
    .tier-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .tier-card {
      background: #FFFFFF;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 32px 24px;
      position: relative;
      display: flex;
      flex-direction: column;
    }
    .tier-card.featured {
      border: 2px solid var(--brand-green);
      box-shadow: var(--shadow-lg);
    }
    .tier-ribbon {
      position: absolute;
      top: -12px;
      right: 20px;
      background: var(--brand-green);
      color: #fff;
      font-size: 11px;
      font-weight: 700;
      padding: 2px 10px;
      border-radius: 20px;
    }
    .tier-title {
      font-size: 20px;
      font-weight: 700;
      margin-bottom: 8px;
    }
    .tier-desc {
      font-size: 13px;
      color: var(--text-muted);
      margin-bottom: 24px;
    }
    .tier-price {
      font-size: 32px;
      font-weight: 800;
      font-family: var(--font-mono);
      margin-bottom: 24px;
    }
    .tier-list {
      list-style: none;
      margin-bottom: 32px;
      flex: 1;
    }
    .tier-item {
      font-size: 14px;
      color: var(--text-secondary);
      padding: 8px 0;
      display: flex;
      align-items: center;
      gap: 10px;
    }
    .tier-item i {
      color: var(--brand-green);
      font-size: 12px;
    }

    /* Section 6: Workflow Pipeline */
    .flow-pipeline {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
      position: relative;
    }
    .flow-step {
      background: #FFFFFF;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 24px;
      position: relative;
    }
    .flow-step-num {
      font-size: 32px;
      font-weight: 800;
      font-family: var(--font-mono);
      color: #CBD5E0;
      line-height: 1;
      margin-bottom: 12px;
    }
    .flow-step h4 {
      font-size: 16px;
      font-weight: 600;
      margin-bottom: 8px;
    }
    .flow-step p {
      font-size: 13px;
      color: var(--text-secondary);
      line-height: 1.6;
    }

    /* Section 7: Deep Architecture */
    .arch-grid {
      display: grid;
      grid-template-columns: 1.2fr 1fr;
      gap: 40px;
      align-items: center;
    }
    .code-console {
      background: #0B0D11;
      border: 1px solid var(--border-dark);
      border-radius: var(--radius-md);
      padding: 20px;
      font-family: var(--font-mono);
      font-size: 13px;
      color: #A0AEC0;
      line-height: 1.6;
    }
    .code-line {
      display: block;
      margin-bottom: 4px;
    }
    .code-hl {
      color: #48BB78;
    }
    .code-key {
      color: #63B3ED;
    }

    /* Section 8: Case Studies */
    .case-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 28px;
    }
    .case-card {
      background: #FFFFFF;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 28px;
    }
    .case-tag {
      font-size: 12px;
      padding: 3px 8px;
      background: var(--brand-green-light);
      color: var(--brand-green);
      border-radius: var(--radius-sm);
      font-weight: 600;
    }
    .case-card h4 {
      font-size: 18px;
      font-weight: 600;
      margin: 14px 0 8px;
    }
    .case-card p {
      font-size: 14px;
      color: var(--text-secondary);
      line-height: 1.6;
      margin-bottom: 20px;
    }
    .case-metric {
      display: flex;
      gap: 24px;
      border-top: 1px solid var(--border-light);
      padding-top: 16px;
    }
    .metric-data {
      font-size: 20px;
      font-weight: 700;
      color: var(--brand-green);
      font-family: var(--font-mono);
    }
    .metric-sub {
      font-size: 12px;
      color: var(--text-muted);
    }

    /* Section 9: Metrics Strip */
    .metrics-bar {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
      text-align: center;
    }
    .metric-card {
      padding: 32px 16px;
      background: #FFFFFF;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
    }
    .metric-num {
      font-size: 38px;
      font-weight: 800;
      color: var(--brand-green);
      font-family: var(--font-mono);
      line-height: 1;
      margin-bottom: 8px;
    }
    .metric-label {
      font-size: 13px;
      color: var(--text-secondary);
    }

    /* Section 10: Insights / News */
    .news-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .news-card {
      background: #FFFFFF;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      overflow: hidden;
      display: flex;
      flex-direction: column;
    }
    .news-card-img {
      height: 160px;
      object-fit: cover;
      width: 100%;
    }
    .news-content {
      padding: 20px;
      flex: 1;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
    }
    .news-date {
      font-size: 12px;
      color: var(--text-muted);
      margin-bottom: 6px;
    }
    .news-content h4 {
      font-size: 16px;
      font-weight: 600;
      line-height: 1.4;
      margin-bottom: 10px;
    }
    .news-content p {
      font-size: 13px;
      color: var(--text-secondary);
      line-height: 1.6;
      margin-bottom: 16px;
    }
    .news-action {
      font-size: 13px;
      font-weight: 600;
      color: var(--brand-green);
    }

    /* Section 11: Compliance Trust */
    .cert-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
    }
    .cert-card {
      background: #FFFFFF;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 24px;
      text-align: center;
    }
    .cert-card i {
      font-size: 28px;
      color: var(--brand-green);
      margin-bottom: 14px;
    }
    .cert-card h4 {
      font-size: 15px;
      font-weight: 600;
      margin-bottom: 6px;
    }
    .cert-card p {
      font-size: 12px;
      color: var(--text-muted);
      line-height: 1.5;
    }

    /* Section 12: Testimonials */
    .quote-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .quote-card {
      background: #FFFFFF;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 28px;
      position: relative;
    }
    .quote-icon {
      font-size: 24px;
      color: #CBD5E0;
      margin-bottom: 14px;
    }
    .quote-card p {
      font-size: 14px;
      color: var(--text-secondary);
      line-height: 1.7;
      margin-bottom: 20px;
      font-style: italic;
    }
    .quote-author {
      font-size: 14px;
      font-weight: 600;
      color: var(--text-main);
    }
    .quote-role {
      font-size: 12px;
      color: var(--text-muted);
    }

    /* Section 13: FAQ Accordion */
    .faq-container {
      max-width: 820px;
      margin: 0 auto;
    }
    .faq-item {
      background: #FFFFFF;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      margin-bottom: 12px;
      overflow: hidden;
    }
    .faq-header {
      padding: 20px 24px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      user-select: none;
    }
    .faq-title {
      font-size: 16px;
      font-weight: 600;
      color: var(--text-main);
    }
    .faq-toggle {
      font-size: 14px;
      color: var(--text-muted);
      transition: var(--transition);
    }
    .faq-body {
      padding: 0 24px 20px;
      font-size: 14px;
      color: var(--text-secondary);
      line-height: 1.7;
      display: none;
    }
    .faq-item.active .faq-body {
      display: block;
    }
    .faq-item.active .faq-toggle {
      transform: rotate(180deg);
      color: var(--brand-green);
    }

    /* Section 14: CTA Portal & Form */
    .cta-container {
      background: #141820;
      border-radius: var(--radius-lg);
      padding: 56px 48px;
      color: #FFFFFF;
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .cta-info h3 {
      font-size: 28px;
      font-weight: 700;
      margin-bottom: 14px;
    }
    .cta-info p {
      font-size: 15px;
      color: #A0AEC0;
      line-height: 1.7;
      margin-bottom: 24px;
    }
    .cta-form {
      background: #1F2430;
      border: 1px solid var(--border-dark);
      border-radius: var(--radius-md);
      padding: 28px;
    }
    .form-group {
      margin-bottom: 16px;
    }
    .form-label {
      display: block;
      font-size: 13px;
      color: #CBD5E0;
      margin-bottom: 6px;
    }
    .form-control {
      width: 100%;
      padding: 10px 14px;
      background: #0D1017;
      border: 1px solid var(--border-dark);
      border-radius: var(--radius-sm);
      color: #FFFFFF;
      font-size: 14px;
      outline: none;
    }
    .form-control:focus {
      border-color: var(--brand-green);
    }

    /* Footer */
    .site-footer {
      background: var(--bg-dark);
      color: #A0AEC0;
      padding: 70px 0 30px;
      border-top: 1px solid #1A202C;
      font-size: 13px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 1.5fr repeat(3, 1fr);
      gap: 40px;
      margin-bottom: 50px;
    }
    .footer-brand h4 {
      font-size: 18px;
      font-weight: 700;
      color: #FFFFFF;
      margin-bottom: 14px;
    }
    .footer-brand p {
      line-height: 1.7;
      margin-bottom: 16px;
      max-width: 300px;
    }
    .footer-col h5 {
      font-size: 14px;
      font-weight: 600;
      color: #FFFFFF;
      margin-bottom: 18px;
    }
    .footer-links {
      list-style: none;
    }
    .footer-links li {
      margin-bottom: 10px;
    }
    .footer-links a:hover {
      color: var(--brand-green);
    }
    .footer-bottom {
      border-top: 1px solid #1A202C;
      padding-top: 24px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-size: 12px;
      color: #718096;
    }

    /* Mobile Nav Toggle */
    .mobile-nav-btn {
      display: none;
      background: none;
      border: none;
      font-size: 20px;
      color: var(--text-main);
      cursor: pointer;
    }

    /* Responsive Queries */
    @media (max-width: 1024px) {
      .hero-h1 { font-size: 38px; }
      .series-grid { grid-template-columns: repeat(2, 1fr); }
      .cert-grid { grid-template-columns: repeat(2, 1fr); }
      .flow-pipeline { grid-template-columns: repeat(2, 1fr); }
      .metrics-bar { grid-template-columns: repeat(2, 1fr); }
      .arch-grid { grid-template-columns: 1fr; }
      .cta-container { grid-template-columns: 1fr; gap: 30px; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }

    @media (max-width: 768px) {
      .top-bar { display: none; }
      .nav-menu { display: none; }
      .mobile-nav-btn { display: block; }
      .story-grid { grid-template-columns: 1fr; }
      .hot-grid { grid-template-columns: 1fr; }
      .tier-grid { grid-template-columns: 1fr; }
      .case-grid { grid-template-columns: 1fr; }
      .news-grid { grid-template-columns: 1fr; }
      .quote-grid { grid-template-columns: 1fr; }
      .metrics-bar { grid-template-columns: 1fr; }
      .cert-grid { grid-template-columns: 1fr; }
      .flow-pipeline { grid-template-columns: 1fr; }
      .hero-h1 { font-size: 28px; }
      .section-title { font-size: 24px; }
      .footer-grid { grid-template-columns: 1fr; }
      .footer-bottom { flex-direction: column; gap: 12px; text-align: center; }
      .cta-container { padding: 32px 20px; }
    }