/* roulang page: index */
:root {
      --bg-dark: #0A0D14;
      --bg-surface: #121722;
      --bg-surface-elevated: #1A2232;
      --bg-light: #F7F8FA;
      --bg-white: #FFFFFF;
      --accent-green: #00FF9D;
      --accent-blue: #2D62FF;
      --accent-cyan: #00E5FF;
      --accent-purple: #7928CA;
      --text-main-dark: #0A0D14;
      --text-sub-dark: #4A5568;
      --text-main-light: #FFFFFF;
      --text-sub-light: #A0AEC0;
      --text-muted: #718096;
      --border-dark: rgba(255, 255, 255, 0.08);
      --border-light: rgba(0, 0, 0, 0.08);
      --radius-sm: 6px;
      --radius-md: 12px;
      --radius-lg: 20px;
      --shadow-sm: 0 4px 12px rgba(0, 0, 0, 0.05);
      --shadow-md: 0 12px 32px rgba(0, 0, 0, 0.08);
      --shadow-glow: 0 0 25px rgba(0, 255, 157, 0.2);
      --transition-smooth: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    }

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

    html {
      scroll-behavior: smooth;
    }

    body {
      font-family: system-ui, -apple-system, 'Segoe UI', Roboto, 'PingFang SC', 'Microsoft YaHei', sans-serif;
      background-color: var(--bg-dark);
      color: var(--text-main-light);
      line-height: 1.65;
      font-size: 16px;
      overflow-x: hidden;
      -webkit-font-smoothing: antialiased;
    }

    a {
      color: inherit;
      text-decoration: none;
      transition: var(--transition-smooth);
    }
    a:hover, a:focus {
      color: var(--accent-green);
    }

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

    /* Top Info Bar */
    .top-info-bar {
      height: 38px;
      background: #06080D;
      border-bottom: 1px solid var(--border-dark);
      font-size: 0.8rem;
      color: var(--text-muted);
      display: flex;
      align-items: center;
      z-index: 1001;
      position: relative;
    }
    .top-info-bar .grid-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    .status-indicator {
      display: inline-flex;
      align-items: center;
      gap: 6px;
    }
    .status-dot {
      width: 7px;
      height: 7px;
      background: var(--accent-green);
      border-radius: 50%;
      box-shadow: 0 0 8px var(--accent-green);
    }

    /* Main Sticky Header */
    .site-header {
      position: sticky;
      top: 0;
      background: rgba(10, 13, 20, 0.85);
      backdrop-filter: blur(16px);
      -webkit-backdrop-filter: blur(16px);
      border-bottom: 1px solid var(--border-dark);
      z-index: 1000;
      padding: 0.85rem 0;
    }
    .site-nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
    }
    .brand-logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-size: 1.25rem;
      font-weight: 800;
      color: #fff;
      letter-spacing: -0.5px;
    }
    .brand-badge {
      font-size: 0.7rem;
      padding: 2px 8px;
      background: rgba(0, 255, 157, 0.12);
      color: var(--accent-green);
      border: 1px solid rgba(0, 255, 157, 0.3);
      border-radius: 20px;
      font-weight: 600;
      letter-spacing: 0;
    }
    .main-menu {
      display: flex;
      list-style: none;
      margin: 0;
      gap: 1.5rem;
      align-items: center;
    }
    .main-menu a {
      font-size: 0.92rem;
      font-weight: 500;
      color: var(--text-sub-light);
    }
    .main-menu a:hover, .main-menu a.is-active {
      color: #ffffff;
    }

    /* Custom Button Tokens */
    .btn-primary {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      background: var(--accent-green);
      color: var(--bg-dark) !important;
      font-weight: 700;
      padding: 0.65rem 1.4rem;
      border-radius: var(--radius-sm);
      transition: var(--transition-smooth);
      border: 1px solid var(--accent-green);
      cursor: pointer;
      font-size: 0.92rem;
    }
    .btn-primary:hover {
      background: #00e08a;
      box-shadow: var(--shadow-glow);
      transform: translateY(-2px);
    }
    .btn-secondary {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      background: rgba(255, 255, 255, 0.05);
      color: #FFFFFF !important;
      font-weight: 600;
      padding: 0.65rem 1.4rem;
      border-radius: var(--radius-sm);
      transition: var(--transition-smooth);
      border: 1px solid var(--border-dark);
      cursor: pointer;
      font-size: 0.92rem;
    }
    .btn-secondary:hover {
      background: rgba(255, 255, 255, 0.12);
      border-color: rgba(255, 255, 255, 0.2);
      transform: translateY(-2px);
    }

    /* Global Section Styles */
    section {
      padding: 5rem 0;
      position: relative;
    }
    .section-light {
      background-color: var(--bg-light);
      color: var(--text-main-dark);
    }
    .section-light .section-desc {
      color: var(--text-sub-dark);
    }
    .section-light .sub-tag {
      background: rgba(45, 98, 255, 0.08);
      color: var(--accent-blue);
      border-color: rgba(45, 98, 255, 0.2);
    }
    .section-light .content-card {
      background: var(--bg-white);
      border: 1px solid var(--border-light);
      color: var(--text-main-dark);
    }
    .section-light .content-card h3,
    .section-light .content-card h4 {
      color: var(--text-main-dark);
    }
    .section-light .content-card p {
      color: var(--text-sub-dark);
    }

    .section-dark-surface {
      background-color: var(--bg-surface);
    }
    .section-header {
      margin-bottom: 3.5rem;
    }
    .sub-tag {
      display: inline-block;
      font-size: 0.75rem;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 1.5px;
      padding: 4px 12px;
      background: rgba(0, 255, 157, 0.08);
      color: var(--accent-green);
      border: 1px solid rgba(0, 255, 157, 0.2);
      border-radius: 30px;
      margin-bottom: 1rem;
    }
    .section-title {
      font-size: 2.2rem;
      font-weight: 800;
      line-height: 1.25;
      letter-spacing: -0.5px;
      margin-bottom: 1rem;
    }
    .section-desc {
      font-size: 1.05rem;
      color: var(--text-sub-light);
      max-width: 680px;
      margin: 0 auto;
      line-height: 1.7;
    }

    /* 1. Hero Section (Blueprinted Coupon Entrance & High Impact) */
    .hero-section {
      background: linear-gradient(180deg, rgba(10, 13, 20, 0.7) 0%, rgba(10, 13, 20, 0.95) 100%),
                  url('/assets/images/4c8322be6f990f6c.jpg') center center/cover no-repeat;
      padding: 5.5rem 0 5rem;
      border-bottom: 1px solid var(--border-dark);
    }
    .hero-title {
      font-size: 3.2rem;
      font-weight: 900;
      line-height: 1.18;
      letter-spacing: -1px;
      margin-bottom: 1.5rem;
    }
    .hero-title span {
      background: linear-gradient(90deg, #FFFFFF, var(--accent-green));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }
    .hero-desc {
      font-size: 1.15rem;
      color: var(--text-sub-light);
      line-height: 1.75;
      margin-bottom: 2rem;
    }
    .coupon-card-main {
      background: linear-gradient(135deg, rgba(26, 34, 50, 0.95), rgba(18, 23, 34, 0.95));
      border: 1px dashed rgba(0, 255, 157, 0.5);
      border-radius: var(--radius-lg);
      padding: 2.2rem;
      position: relative;
      box-shadow: 0 16px 40px rgba(0, 0, 0, 0.4);
      backdrop-filter: blur(10px);
    }
    .coupon-card-main::before, .coupon-card-main::after {
      content: '';
      position: absolute;
      width: 20px;
      height: 20px;
      background: var(--bg-dark);
      border-radius: 50%;
      top: 50%;
      transform: translateY(-50%);
    }
    .coupon-card-main::before { left: -10px; }
    .coupon-card-main::after { right: -10px; }
    .coupon-value {
      font-size: 2.8rem;
      font-weight: 900;
      color: var(--accent-green);
      line-height: 1;
    }
    .coupon-meta {
      font-size: 0.88rem;
      color: var(--text-sub-light);
      margin-top: 0.4rem;
    }
    .coupon-tag-stack {
      display: flex;
      gap: 0.5rem;
      flex-wrap: wrap;
      margin: 1.2rem 0;
    }
    .coupon-tag {
      background: rgba(255, 255, 255, 0.06);
      font-size: 0.78rem;
      padding: 3px 10px;
      border-radius: 4px;
      color: #E2E8F0;
    }

    /* 2. KPI / Metrics Section */
    .kpi-card {
      background: var(--bg-surface);
      border: 1px solid var(--border-dark);
      border-radius: var(--radius-md);
      padding: 2rem 1.5rem;
      text-align: center;
      transition: var(--transition-smooth);
    }
    .kpi-card:hover {
      border-color: rgba(0, 255, 157, 0.3);
      transform: translateY(-4px);
    }
    .kpi-number {
      font-size: 2.5rem;
      font-weight: 800;
      color: var(--accent-green);
      line-height: 1.2;
      margin-bottom: 0.5rem;
    }
    .kpi-label {
      font-size: 1rem;
      font-weight: 600;
      color: #FFFFFF;
      margin-bottom: 0.3rem;
    }
    .kpi-sub {
      font-size: 0.82rem;
      color: var(--text-muted);
    }

    /* 3. Pain Points Matrix */
    .pain-card {
      background: var(--bg-surface);
      border: 1px solid var(--border-dark);
      border-radius: var(--radius-md);
      padding: 2rem;
      height: 100%;
      border-left: 3px solid #E53E3E;
      transition: var(--transition-smooth);
    }
    .pain-card:hover {
      transform: translateY(-3px);
      box-shadow: var(--shadow-md);
    }
    .pain-title {
      font-size: 1.15rem;
      font-weight: 700;
      color: #FFF;
      margin-bottom: 0.8rem;
    }
    .pain-text {
      font-size: 0.9rem;
      color: var(--text-sub-light);
      line-height: 1.6;
    }

    /* 4. Service Matrix / Engine Solutions */
    .matrix-card {
      border-radius: var(--radius-md);
      overflow: hidden;
      height: 100%;
      display: flex;
      flex-direction: column;
      transition: var(--transition-smooth);
    }
    .matrix-card:hover {
      transform: translateY(-4px);
    }
    .matrix-card img {
      width: 100%;
      height: 200px;
      object-fit: cover;
    }
    .matrix-body {
      padding: 1.8rem;
      flex-grow: 1;
    }

    /* 5. Workflow Timeline */
    .step-node {
      position: relative;
      background: var(--bg-surface);
      border: 1px solid var(--border-dark);
      border-radius: var(--radius-md);
      padding: 1.8rem;
      height: 100%;
    }
    .step-number {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      width: 32px;
      height: 32px;
      border-radius: 50%;
      background: rgba(0, 255, 157, 0.15);
      color: var(--accent-green);
      font-weight: 800;
      font-size: 0.85rem;
      margin-bottom: 1rem;
    }

    /* 6. Product Presets */
    .preset-card {
      background: var(--bg-surface-elevated);
      border: 1px solid var(--border-dark);
      border-radius: var(--radius-md);
      padding: 2rem;
      height: 100%;
      transition: var(--transition-smooth);
    }
    .preset-card:hover {
      border-color: var(--accent-cyan);
      transform: translateY(-4px);
    }
    .preset-spec-list {
      list-style: none;
      margin: 1.2rem 0;
      padding: 0;
    }
    .preset-spec-list li {
      font-size: 0.88rem;
      color: var(--text-sub-light);
      padding: 0.4rem 0;
      border-bottom: 1px solid rgba(255, 255, 255, 0.04);
      display: flex;
      justify-content: space-between;
    }

    /* 7. Comparison Table */
    .compare-table {
      width: 100%;
      border-collapse: collapse;
      margin-top: 1.5rem;
      background: var(--bg-surface);
      border-radius: var(--radius-md);
      overflow: hidden;
      border: 1px solid var(--border-dark);
    }
    .compare-table th, .compare-table td {
      padding: 1.2rem;
      text-align: left;
      font-size: 0.95rem;
      border-bottom: 1px solid var(--border-dark);
    }
    .compare-table th {
      background: var(--bg-surface-elevated);
      font-weight: 700;
      color: #FFF;
    }
    .compare-table td.highlight {
      color: var(--accent-green);
      font-weight: 600;
    }

    /* 8. Deep Tech Banner */
    .deep-tech-box {
      background: linear-gradient(135deg, #0d121c 0%, #161f30 100%);
      border: 1px solid rgba(45, 98, 255, 0.3);
      border-radius: var(--radius-lg);
      padding: 3.5rem 2.5rem;
    }

    /* 9. Milestones */
    .milestone-item {
      border-left: 2px solid var(--accent-blue);
      padding-left: 1.5rem;
      position: relative;
      margin-bottom: 2rem;
    }
    .milestone-item::before {
      content: '';
      position: absolute;
      left: -6px;
      top: 4px;
      width: 10px;
      height: 10px;
      background: var(--accent-blue);
      border-radius: 50%;
    }

    /* 10. News & Insights */
    .news-card {
      background: var(--bg-white);
      border-radius: var(--radius-md);
      border: 1px solid var(--border-light);
      overflow: hidden;
      height: 100%;
      transition: var(--transition-smooth);
    }
    .news-card:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-3px);
    }
    .news-body {
      padding: 1.6rem;
    }
    .news-date {
      font-size: 0.8rem;
      color: var(--text-muted);
      margin-bottom: 0.5rem;
    }

    /* 11. Security & Guarantee */
    .guarantee-badge {
      display: flex;
      gap: 1.2rem;
      background: var(--bg-surface);
      border: 1px solid var(--border-dark);
      padding: 1.8rem;
      border-radius: var(--radius-md);
    }
    .guarantee-icon {
      font-size: 2rem;
      color: var(--accent-green);
      flex-shrink: 0;
    }

    /* 12. Quick FAQ Accordion */
    .faq-block {
      max-width: 860px;
      margin: 0 auto;
    }
    .accordion-item-custom {
      background: var(--bg-surface);
      border: 1px solid var(--border-dark);
      border-radius: var(--radius-sm);
      margin-bottom: 0.85rem;
      overflow: hidden;
    }
    .accordion-btn {
      width: 100%;
      padding: 1.2rem 1.5rem;
      text-align: left;
      background: none;
      border: none;
      color: #FFFFFF;
      font-weight: 600;
      font-size: 1.05rem;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
    }
    .accordion-content-custom {
      padding: 0 1.5rem 1.4rem;
      color: var(--text-sub-light);
      font-size: 0.95rem;
      line-height: 1.68;
    }

    /* Fixed Bottom Action Bar */
    .bottom-bar {
      position: fixed;
      bottom: 0;
      left: 0;
      right: 0;
      background: rgba(10, 13, 20, 0.94);
      border-top: 1px solid rgba(0, 255, 157, 0.3);
      padding: 0.8rem 0;
      backdrop-filter: blur(12px);
      z-index: 999;
      box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.5);
    }
    .bottom-bar-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
    }

    /* Site Footer */
    .site-footer {
      background: #06080D;
      border-top: 1px solid var(--border-dark);
      padding: 5rem 0 7rem;
      color: var(--text-muted);
      font-size: 0.88rem;
    }
    .footer-title {
      font-size: 1rem;
      font-weight: 700;
      color: #FFFFFF;
      margin-bottom: 1.2rem;
    }
    .footer-links {
      list-style: none;
      margin: 0;
      padding: 0;
    }
    .footer-links li {
      margin-bottom: 0.6rem;
    }
    .footer-links a {
      color: var(--text-muted);
    }
    .footer-links a:hover {
      color: var(--accent-green);
    }
    .footer-bottom {
      margin-top: 4rem;
      padding-top: 2rem;
      border-top: 1px solid rgba(255, 255, 255, 0.05);
      display: flex;
      flex-wrap: wrap;
      justify-content: space-between;
      gap: 1rem;
      align-items: center;
    }

    /* Responsive Queries */
    @media screen and (max-width: 1024px) {
      .hero-title { font-size: 2.5rem; }
      .section-title { font-size: 1.8rem; }
    }
    @media screen and (max-width: 768px) {
      .top-info-bar { display: none; }
      .main-menu { display: none; }
      .hero-title { font-size: 2.1rem; }
      .hero-section { padding: 3.5rem 0; }
      section { padding: 3.5rem 0; }
      .bottom-bar-text { display: none; }
      .coupon-card-main { margin-top: 2rem; }
    }