/* roulang page: index */
:root {
      --brand-primary: #1D63FF;
      --brand-primary-hover: #0E4EDD;
      --brand-accent: #00C5A0;
      --brand-dark: #0E1E38;
      --brand-dark-card: #15294A;
      --bg-white: #FFFFFF;
      --bg-light: #F5F7FA;
      --text-main: #1A202C;
      --text-muted: #4A5568;
      --text-light: #718096;
      --border-color: #E2E8F0;
      --shadow-sm: 0 4px 12px rgba(14, 30, 56, 0.03);
      --shadow-card: 0 8px 24px rgba(14, 30, 56, 0.05);
      --shadow-hover: 0 16px 36px rgba(29, 99, 255, 0.12);
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-lg: 16px;
      --sidebar-width: 260px;
    }

    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
      color: var(--text-main);
      background-color: var(--bg-light);
      line-height: 1.65;
      -webkit-font-smoothing: antialiased;
    }

    a { text-decoration: none; color: inherit; transition: all 0.25s ease; }
    img { max-width: 100%; height: auto; display: block; }
    h1, h2, h3, h4, h5, h6 { font-weight: 700; color: var(--text-main); }

    /* Layout: Fixed Vertical Sidebar on Desktop */
    .app-layout {
      display: flex;
      min-height: 100vh;
    }

    .app-sidebar {
      width: var(--sidebar-width);
      background: #FFFFFF;
      border-right: 1px solid var(--border-color);
      position: fixed;
      top: 0;
      bottom: 0;
      left: 0;
      z-index: 1000;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
      padding: 32px 20px;
    }

    .brand-logo-wrap {
      display: flex;
      align-items: center;
      gap: 12px;
      padding-bottom: 24px;
      border-bottom: 1px solid var(--border-color);
    }
    .brand-icon-badge {
      width: 40px;
      height: 40px;
      background: linear-gradient(135deg, var(--brand-primary), #4F8BFF);
      color: #FFF;
      display: flex;
      align-items: center;
      justify-content: center;
      border-radius: var(--radius-sm);
      font-weight: bold;
      font-size: 20px;
    }
    .brand-title {
      font-size: 19px;
      font-weight: 700;
      color: var(--brand-dark);
      letter-spacing: -0.5px;
    }

    .sidebar-nav-menu {
      list-style: none;
      margin: 28px 0 auto 0;
      display: flex;
      flex-direction: column;
      gap: 8px;
    }
    .sidebar-nav-menu li a {
      display: flex;
      align-items: center;
      gap: 12px;
      padding: 12px 16px;
      border-radius: var(--radius-sm);
      color: var(--text-muted);
      font-size: 15px;
      font-weight: 500;
    }
    .sidebar-nav-menu li a:hover,
    .sidebar-nav-menu li a.active {
      background: rgba(29, 99, 255, 0.08);
      color: var(--brand-primary);
      font-weight: 600;
    }

    .sidebar-cta-box {
      background: var(--bg-light);
      padding: 16px;
      border-radius: var(--radius-md);
      border: 1px solid var(--border-color);
      text-align: center;
    }
    .sidebar-cta-box p {
      font-size: 13px;
      color: var(--text-muted);
      margin-bottom: 12px;
    }

    /* Content Area */
    .app-main {
      margin-left: var(--sidebar-width);
      flex: 1;
      min-width: 0;
      background: #FFFFFF;
    }

    /* Mobile Header */
    .mobile-header {
      display: none;
      height: 64px;
      background: #FFFFFF;
      border-bottom: 1px solid var(--border-color);
      position: sticky;
      top: 0;
      z-index: 999;
      padding: 0 20px;
      align-items: center;
      justify-content: space-between;
    }

    /* Common Components */
    .content-container {
      max-width: 1140px;
      margin: 0 auto;
      padding: 0 32px;
    }
    .section-spacing {
      padding: 96px 0;
    }
    .section-spacing-sm {
      padding: 64px 0;
    }
    .bg-light-alt {
      background-color: var(--bg-light);
    }
    .bg-dark-contrast {
      background-color: var(--brand-dark);
      color: #FFFFFF;
    }

    .section-head {
      margin-bottom: 56px;
    }
    .section-head.center {
      text-align: center;
    }
    .section-tag {
      display: inline-block;
      font-size: 13px;
      font-weight: 600;
      color: var(--brand-primary);
      background: rgba(29, 99, 255, 0.08);
      padding: 4px 14px;
      border-radius: 20px;
      margin-bottom: 12px;
      text-transform: uppercase;
    }
    .section-tag.light {
      background: rgba(0, 197, 160, 0.15);
      color: var(--brand-accent);
    }
    .section-title {
      font-size: 32px;
      line-height: 1.35;
      margin-bottom: 16px;
      color: inherit;
    }
    .section-desc {
      font-size: 16px;
      color: var(--text-muted);
      max-width: 780px;
      line-height: 1.7;
    }
    .bg-dark-contrast .section-desc {
      color: #A0AEC0;
    }

    .btn-primary {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 14px 28px;
      background-color: var(--brand-primary);
      color: #FFFFFF;
      font-size: 15px;
      font-weight: 600;
      border-radius: var(--radius-sm);
      border: 1px solid transparent;
      box-shadow: 0 4px 14px rgba(29, 99, 255, 0.28);
      cursor: pointer;
    }
    .btn-primary:hover {
      background-color: var(--brand-primary-hover);
      color: #FFF;
      transform: translateY(-2px);
      box-shadow: 0 6px 20px rgba(29, 99, 255, 0.36);
    }
    .btn-secondary {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 14px 28px;
      background-color: transparent;
      color: var(--brand-dark);
      font-size: 15px;
      font-weight: 600;
      border-radius: var(--radius-sm);
      border: 1px solid var(--border-color);
      cursor: pointer;
    }
    .btn-secondary:hover {
      background-color: #FFF;
      border-color: var(--brand-primary);
      color: var(--brand-primary);
    }

    .ui-card {
      background: #FFFFFF;
      border-radius: var(--radius-md);
      border: 1px solid var(--border-color);
      padding: 32px;
      box-shadow: var(--shadow-card);
      transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
      height: 100%;
      display: flex;
      flex-direction: column;
    }
    .ui-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
      border-color: rgba(29, 99, 255, 0.2);
    }

    /* Section 1: Hero Before/After Structure */
    .hero-section {
      padding: 72px 0 88px 0;
      background: linear-gradient(180deg, #F8FAFC 0%, #FFFFFF 100%);
      border-bottom: 1px solid var(--border-color);
    }
    .hero-h1 {
      font-size: 42px;
      line-height: 1.25;
      font-weight: 800;
      color: var(--brand-dark);
      margin-bottom: 20px;
      letter-spacing: -0.5px;
    }
    .hero-desc {
      font-size: 17px;
      color: var(--text-muted);
      line-height: 1.75;
      margin-bottom: 36px;
    }
    .hero-actions {
      display: flex;
      gap: 16px;
      margin-bottom: 48px;
      flex-wrap: wrap;
    }
    
    .compare-container {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 24px;
      margin-top: 16px;
    }
    .compare-box {
      border-radius: var(--radius-md);
      padding: 28px;
      position: relative;
    }
    .compare-box.before {
      background: #FFF5F5;
      border: 1px solid #FED7D7;
    }
    .compare-box.after {
      background: #F0FDF4;
      border: 1px solid #BBF7D0;
    }
    .compare-badge {
      display: inline-block;
      padding: 4px 10px;
      border-radius: 4px;
      font-size: 12px;
      font-weight: 700;
      margin-bottom: 12px;
    }
    .compare-box.before .compare-badge { background: #E53E3E; color: #FFF; }
    .compare-box.after .compare-badge { background: var(--brand-accent); color: #FFF; }
    .compare-list {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 10px;
      font-size: 14px;
      color: var(--text-muted);
    }

    /* Section 2: Catalog Grid */
    .catalog-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }

    /* Section 3: Value Points (6 cards) */
    .value-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .feature-icon-bar {
      width: 48px;
      height: 48px;
      border-radius: var(--radius-sm);
      background: rgba(29, 99, 255, 0.08);
      color: var(--brand-primary);
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 22px;
      margin-bottom: 20px;
    }

    /* Section 4: Metrics Dashboard */
    .metric-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
    }
    .metric-card {
      background: #FFFFFF;
      padding: 28px 20px;
      border-radius: var(--radius-md);
      border: 1px solid var(--border-color);
      text-align: center;
    }
    .metric-val {
      font-size: 40px;
      font-weight: 800;
      color: var(--brand-primary);
      line-height: 1.1;
      margin-bottom: 8px;
    }
    .metric-label {
      font-size: 14px;
      font-weight: 600;
      color: var(--text-main);
      margin-bottom: 4px;
    }
    .metric-sub {
      font-size: 12px;
      color: var(--text-light);
    }

    /* Section 5: Step Process */
    .step-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
      position: relative;
    }
    .step-card {
      position: relative;
      background: #FFF;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      padding: 24px;
    }
    .step-num {
      width: 32px;
      height: 32px;
      border-radius: 50%;
      background: var(--brand-primary);
      color: #FFF;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      font-size: 14px;
      margin-bottom: 16px;
    }

    /* Section 6: Dark Contrast Case Study */
    .dark-case-card {
      background: var(--brand-dark-card);
      border: 1px solid rgba(255, 255, 255, 0.1);
      border-radius: var(--radius-lg);
      padding: 40px;
    }
    .case-flow-box {
      background: rgba(0, 0, 0, 0.2);
      border-radius: var(--radius-sm);
      padding: 20px;
      margin-top: 24px;
      border-left: 4px solid var(--brand-accent);
    }

    /* Section 7: User Story Cards */
    .review-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .user-profile {
      display: flex;
      align-items: center;
      gap: 12px;
      margin-top: auto;
      padding-top: 20px;
      border-top: 1px solid var(--border-color);
    }
    .avatar-mock {
      width: 44px;
      height: 44px;
      border-radius: 50%;
      background: var(--bg-light);
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: bold;
      color: var(--brand-primary);
      border: 1px solid var(--border-color);
    }

    /* Section 8: Tech Certification / Specs */
    .specs-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 40px;
      align-items: center;
    }
    .spec-item {
      display: flex;
      gap: 16px;
      margin-bottom: 20px;
    }
    .spec-bullet {
      width: 8px;
      height: 8px;
      border-radius: 50%;
      background: var(--brand-primary);
      margin-top: 8px;
    }

    /* Section 9: Articles / News */
    .news-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .news-card-img {
      height: 180px;
      width: 100%;
      object-fit: cover;
      border-radius: var(--radius-sm);
      margin-bottom: 16px;
    }

    /* Section 10: Partners Wall */
    .partner-grid {
      display: grid;
      grid-template-columns: repeat(6, 1fr);
      gap: 16px;
    }
    .partner-item {
      background: #FFFFFF;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-sm);
      padding: 20px;
      text-align: center;
      font-weight: 600;
      color: var(--text-light);
      transition: all 0.2s;
    }
    .partner-item:hover {
      color: var(--brand-primary);
      border-color: var(--brand-primary);
      transform: translateY(-2px);
    }

    /* Section 11: FAQ Accordion */
    .faq-container {
      max-width: 840px;
      margin: 0 auto;
    }
    .faq-item {
      background: #FFFFFF;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      margin-bottom: 16px;
      overflow: hidden;
    }
    .faq-question {
      padding: 20px 24px;
      font-weight: 600;
      font-size: 17px;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .faq-answer {
      padding: 0 24px 20px 24px;
      color: var(--text-muted);
      font-size: 15px;
      line-height: 1.7;
    }

    /* Section 12: SLA + Final CTA Form */
    .sla-banner {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
      padding: 32px;
      background: #FFFFFF;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      margin-bottom: 40px;
    }
    .cta-lead-form {
      background: linear-gradient(135deg, #1D63FF 0%, #0E4EDD 100%);
      border-radius: var(--radius-lg);
      padding: 56px 40px;
      color: #FFFFFF;
      text-align: center;
    }
    .lead-input-group {
      max-width: 540px;
      margin: 32px auto 0 auto;
      display: flex;
      gap: 12px;
    }
    .lead-input-group input {
      flex: 1;
      height: 48px;
      padding: 0 16px;
      border-radius: var(--radius-sm);
      border: 1px solid transparent;
      outline: none;
      font-size: 15px;
    }
    .lead-input-group button {
      height: 48px;
      padding: 0 28px;
      background: var(--brand-accent);
      color: #FFFFFF;
      font-weight: 700;
      border: none;
      border-radius: var(--radius-sm);
      cursor: pointer;
      white-space: nowrap;
    }

    /* Footer */
    .app-footer {
      background: var(--brand-dark);
      color: #A0AEC0;
      padding: 72px 0 32px 0;
      border-top: 1px solid rgba(255, 255, 255, 0.1);
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
      margin-bottom: 48px;
    }
    .footer-col h4 {
      color: #FFFFFF;
      font-size: 16px;
      margin-bottom: 20px;
    }
    .footer-col ul {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 10px;
      font-size: 14px;
    }
    .footer-bottom {
      border-top: 1px solid rgba(255, 255, 255, 0.08);
      padding-top: 24px;
      font-size: 13px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      gap: 12px;
    }

    /* Responsive */
    @media (max-width: 1024px) {
      .app-sidebar { display: none; }
      .app-main { margin-left: 0; }
      .mobile-header { display: flex; }
      .catalog-grid, .value-grid, .review-grid, .news-grid { grid-template-columns: repeat(2, 1fr); }
      .metric-grid, .step-grid { grid-template-columns: repeat(2, 1fr); }
      .partner-grid { grid-template-columns: repeat(3, 1fr); }
      .footer-grid { grid-template-columns: 1fr 1fr; }
      .specs-grid { grid-template-columns: 1fr; }
    }

    @media (max-width: 768px) {
      .compare-container { grid-template-columns: 1fr; }
      .catalog-grid, .value-grid, .review-grid, .news-grid { grid-template-columns: 1fr; }
      .metric-grid, .step-grid { grid-template-columns: 1fr; }
      .sla-banner { grid-template-columns: 1fr; }
      .lead-input-group { flex-direction: column; }
      .lead-input-group button { width: 100%; }
      .hero-h1 { font-size: 30px; }
      .section-title { font-size: 24px; }
      .footer-grid { grid-template-columns: 1fr; }
      .section-spacing { padding: 60px 0; }
    }