/* roulang page: index */
:root {
      --bg-base: #F8F9FA;
      --bg-white: #FFFFFF;
      --bg-dark: #0B0F17;
      --bg-dark-card: #141B26;
      --primary: #0F172A;
      --primary-accent: #15803D;
      --primary-accent-hover: #047857;
      --text-main: #1E293B;
      --text-muted: #64748B;
      --text-light: #94A3B8;
      --border-color: #E2E8F0;
      --border-dark: #1E293B;
      --radius-sm: 4px;
      --radius-md: 6px;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.05);
      --shadow-card: 0 1px 3px rgba(0,0,0,0.05), 0 10px 25px -5px rgba(0,0,0,0.03);
      --container-max: 1200px;
    }

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

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

    body {
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      background-color: var(--bg-base);
      color: var(--text-main);
      line-height: 1.65;
      -webkit-font-smoothing: antialiased;
    }

    a {
      color: inherit;
      text-decoration: none;
      transition: all 0.2s ease;
    }

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

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

    /* Top Meta Bar */
    .top-bar {
      background-color: #080C13;
      color: var(--text-light);
      font-size: 13px;
      padding: 8px 0;
      border-bottom: 1px solid rgba(255,255,255,0.08);
    }
    .top-bar-inner {
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .top-bar-meta {
      display: flex;
      gap: 20px;
    }
    .top-bar-status {
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .status-dot {
      width: 8px;
      height: 8px;
      background-color: #10B981;
      border-radius: 50%;
      box-shadow: 0 0 6px rgba(16,185,129,0.8);
    }

    /* Sticky Navigation */
    .main-nav {
      position: sticky;
      top: 0;
      z-index: 1000;
      background: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(10px);
      border-bottom: 1px solid var(--border-color);
      transition: background 0.3s;
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .nav-logo {
      font-size: 20px;
      font-weight: 700;
      color: var(--primary);
      letter-spacing: -0.02em;
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .nav-logo-mark {
      width: 12px;
      height: 12px;
      background-color: var(--primary-accent);
      border-radius: 2px;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 24px;
      list-style: none;
    }
    .nav-links a {
      font-size: 14px;
      font-weight: 500;
      color: var(--text-muted);
    }
    .nav-links a:hover {
      color: var(--primary-accent);
    }
    .nav-action-btn {
      display: inline-flex;
      align-items: center;
      padding: 9px 18px;
      font-size: 14px;
      font-weight: 600;
      color: var(--primary);
      border: 1px solid var(--primary);
      border-radius: var(--radius-sm);
      background: transparent;
      cursor: pointer;
    }
    .nav-action-btn:hover {
      background: var(--primary);
      color: #fff;
    }

    /* Section Global */
    section {
      padding: clamp(3.5rem, 6vw, 6rem) 0;
      scroll-margin-top: 80px;
    }
    .section-alt {
      background-color: var(--bg-white);
      border-top: 1px solid var(--border-color);
      border-bottom: 1px solid var(--border-color);
    }
    .section-dark {
      background-color: var(--bg-dark);
      color: #F8FAFC;
    }
    .section-header {
      margin-bottom: 3rem;
      max-width: 720px;
    }
    .section-tag {
      font-size: 13px;
      font-weight: 700;
      color: var(--primary-accent);
      text-transform: uppercase;
      letter-spacing: 0.05em;
      margin-bottom: 8px;
      display: inline-block;
    }
    .section-title {
      font-size: clamp(26px, 3.2vw, 36px);
      font-weight: 700;
      color: var(--primary);
      letter-spacing: -0.02em;
      line-height: 1.25;
      margin-bottom: 16px;
    }
    .section-dark .section-title {
      color: #F8FAFC;
    }
    .section-desc {
      font-size: 16px;
      color: var(--text-muted);
      line-height: 1.7;
    }
    .section-dark .section-desc {
      color: var(--text-light);
    }

    /* 1. Hero 裂变邀请与矮版架构 */
    .hero-section {
      background: linear-gradient(180deg, #FFFFFF 0%, #F1F5F9 100%);
      padding: clamp(2.5rem, 4vw, 4.5rem) 0;
      border-bottom: 1px solid var(--border-color);
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1.2fr 0.8fr;
      gap: 40px;
      align-items: center;
    }
    .hero-h1 {
      font-size: clamp(30px, 3.8vw, 44px);
      font-weight: 800;
      color: var(--primary);
      line-height: 1.2;
      letter-spacing: -0.025em;
      margin-bottom: 18px;
    }
    .hero-intro {
      font-size: 16px;
      color: #475569;
      line-height: 1.75;
      margin-bottom: 24px;
    }
    .hero-btn-group {
      display: flex;
      gap: 16px;
      margin-bottom: 24px;
    }
    .btn-primary {
      display: inline-flex;
      align-items: center;
      padding: 12px 24px;
      background: var(--primary-accent);
      color: #fff;
      font-size: 15px;
      font-weight: 600;
      border-radius: var(--radius-sm);
      border: 1px solid var(--primary-accent);
      box-shadow: 0 2px 4px rgba(21,128,61,0.2);
    }
    .btn-primary:hover {
      background: var(--primary-accent-hover);
      transform: translateY(-1px);
    }
    .btn-secondary {
      display: inline-flex;
      align-items: center;
      padding: 12px 24px;
      background: #FFFFFF;
      color: var(--primary);
      font-size: 15px;
      font-weight: 600;
      border-radius: var(--radius-sm);
      border: 1px solid var(--border-color);
    }
    .btn-secondary:hover {
      background: #F8FAFC;
      border-color: #CBD5E1;
      transform: translateY(-1px);
    }

    .hero-referral-card {
      background: #FFFFFF;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      padding: 24px;
      box-shadow: var(--shadow-card);
    }
    .referral-header {
      display: flex;
      justify-content: space-between;
      align-items: center;
      margin-bottom: 16px;
    }
    .referral-title {
      font-size: 15px;
      font-weight: 700;
      color: var(--primary);
    }
    .referral-reward {
      font-size: 13px;
      color: var(--primary-accent);
      background: #ECFDF5;
      padding: 4px 8px;
      border-radius: 4px;
      font-weight: 600;
    }
    .referral-desc {
      font-size: 13px;
      color: var(--text-muted);
      margin-bottom: 16px;
      line-height: 1.6;
    }
    .progress-bar-wrap {
      margin-bottom: 16px;
    }
    .progress-labels {
      display: flex;
      justify-content: space-between;
      font-size: 12px;
      color: var(--text-muted);
      margin-bottom: 6px;
    }
    .progress-track {
      background: #E2E8F0;
      height: 8px;
      border-radius: 4px;
      overflow: hidden;
    }
    .progress-fill {
      width: 76%;
      height: 100%;
      background: linear-gradient(90deg, #15803D, #047857);
      border-radius: 4px;
    }
    .referral-cta {
      display: block;
      text-align: center;
      background: var(--primary);
      color: #fff;
      padding: 10px;
      border-radius: var(--radius-sm);
      font-size: 13px;
      font-weight: 600;
    }
    .referral-cta:hover {
      background: #1E293B;
    }

    /* 2. 能力概览 (4栏不对称痛点比对) */
    .challenges-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
    }
    .challenge-card {
      background: var(--bg-white);
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      padding: 24px;
      box-shadow: var(--shadow-sm);
      display: flex;
      flex-direction: column;
      justify-content: space-between;
    }
    .challenge-num {
      font-size: 12px;
      font-weight: 700;
      color: var(--text-muted);
      margin-bottom: 12px;
    }
    .challenge-title {
      font-size: 18px;
      font-weight: 700;
      color: var(--primary);
      margin-bottom: 12px;
    }
    .challenge-trad {
      font-size: 13px;
      color: #94A3B8;
      background: #F8FAFC;
      padding: 8px 12px;
      border-left: 2px solid #CBD5E1;
      margin-bottom: 12px;
      line-height: 1.5;
    }
    .challenge-smart {
      font-size: 14px;
      color: #334155;
      line-height: 1.6;
    }

    /* 3. 架构与产品参数 */
    .arch-grid {
      display: grid;
      grid-template-columns: 1.1fr 0.9fr;
      gap: 40px;
      align-items: center;
    }
    .arch-specs {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 16px;
      margin-top: 24px;
    }
    .spec-item {
      background: #F1F5F9;
      padding: 16px;
      border-radius: var(--radius-sm);
      border-left: 3px solid var(--primary-accent);
    }
    .spec-val {
      font-size: 22px;
      font-weight: 700;
      color: var(--primary);
      margin-bottom: 4px;
    }
    .spec-label {
      font-size: 13px;
      color: var(--text-muted);
    }
    .arch-img-wrap {
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      overflow: hidden;
      box-shadow: var(--shadow-card);
    }

    /* 4. 核心优势 (6卡片网格) */
    .advantages-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .adv-card {
      background: var(--bg-white);
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      padding: 28px 24px;
      box-shadow: var(--shadow-sm);
      transition: all 0.2s;
    }
    .adv-card:hover {
      border-color: #94A3B8;
      transform: translateY(-2px);
      box-shadow: var(--shadow-card);
    }
    .adv-badge {
      font-size: 11px;
      font-weight: 700;
      color: var(--primary-accent);
      background: #ECFDF5;
      padding: 3px 8px;
      border-radius: 4px;
      display: inline-block;
      margin-bottom: 12px;
    }
    .adv-title {
      font-size: 18px;
      font-weight: 700;
      color: var(--primary);
      margin-bottom: 10px;
    }
    .adv-desc {
      font-size: 14px;
      color: var(--text-muted);
      line-height: 1.6;
    }

    /* 5. 方案矩阵 (3栏纵向对比) */
    .solutions-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .solution-card {
      background: var(--bg-white);
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      padding: 32px 24px;
      display: flex;
      flex-direction: column;
      position: relative;
    }
    .solution-card.featured {
      border: 2px solid var(--primary-accent);
      box-shadow: var(--shadow-card);
    }
    .solution-tag {
      position: absolute;
      top: 16px;
      right: 16px;
      font-size: 11px;
      font-weight: 700;
      background: var(--primary);
      color: #fff;
      padding: 2px 8px;
      border-radius: 3px;
    }
    .solution-name {
      font-size: 20px;
      font-weight: 700;
      color: var(--primary);
      margin-bottom: 8px;
    }
    .solution-desc {
      font-size: 14px;
      color: var(--text-muted);
      margin-bottom: 24px;
      min-height: 48px;
    }
    .solution-meta-list {
      list-style: none;
      margin-bottom: 28px;
      flex-grow: 1;
    }
    .solution-meta-list li {
      font-size: 13px;
      color: #334155;
      padding: 8px 0;
      border-bottom: 1px dashed var(--border-color);
      display: flex;
      justify-content: space-between;
    }
    .solution-btn {
      text-align: center;
      padding: 10px;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-sm);
      font-size: 14px;
      font-weight: 600;
      color: var(--primary);
    }
    .solution-card.featured .solution-btn {
      background: var(--primary-accent);
      border-color: var(--primary-accent);
      color: #fff;
    }

    /* 6. 算法理念深色区 */
    .algo-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .algo-flow-box {
      background: var(--bg-dark-card);
      border: 1px solid var(--border-dark);
      border-radius: var(--radius-md);
      padding: 28px;
    }
    .flow-step {
      display: flex;
      gap: 16px;
      margin-bottom: 20px;
      position: relative;
    }
    .flow-step:last-child {
      margin-bottom: 0;
    }
    .flow-num {
      width: 28px;
      height: 28px;
      background: #1E293B;
      color: #38BDF8;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 13px;
      font-weight: 700;
      flex-shrink: 0;
    }
    .flow-text-h {
      font-size: 15px;
      font-weight: 700;
      color: #F8FAFC;
      margin-bottom: 4px;
    }
    .flow-text-p {
      font-size: 13px;
      color: var(--text-light);
      line-height: 1.5;
    }

    /* 7. 机构落地故事 (2栏横向深度卡片) */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 32px;
    }
    .case-card {
      background: var(--bg-white);
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
    }
    .case-img {
      height: 220px;
      object-fit: cover;
      width: 100%;
    }
    .case-body {
      padding: 28px;
    }
    .case-label {
      font-size: 12px;
      font-weight: 700;
      color: var(--primary-accent);
      margin-bottom: 8px;
    }
    .case-title {
      font-size: 20px;
      font-weight: 700;
      color: var(--primary);
      margin-bottom: 12px;
    }
    .case-text {
      font-size: 14px;
      color: var(--text-muted);
      line-height: 1.65;
      margin-bottom: 20px;
    }
    .case-metric-row {
      display: flex;
      gap: 24px;
      padding-top: 16px;
      border-top: 1px solid var(--border-color);
    }
    .case-metric-val {
      font-size: 18px;
      font-weight: 700;
      color: var(--primary);
    }
    .case-metric-lbl {
      font-size: 12px;
      color: var(--text-muted);
    }

    /* 8. 成果数据指标条 */
    .metrics-bar {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 32px;
      text-align: center;
    }
    .metric-cell {
      padding: 20px;
      background: #F8FAFC;
      border-radius: var(--radius-sm);
    }
    .metric-number {
      font-size: clamp(32px, 3.5vw, 42px);
      font-weight: 800;
      color: var(--primary);
      letter-spacing: -0.03em;
      line-height: 1.1;
      margin-bottom: 6px;
    }
    .metric-caption {
      font-size: 14px;
      color: var(--text-muted);
      font-weight: 500;
    }

    /* 9. 客户评价 (3栏) */
    .testimonials-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .testi-card {
      background: var(--bg-white);
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      padding: 24px;
      box-shadow: var(--shadow-sm);
      display: flex;
      flex-direction: column;
      justify-content: space-between;
    }
    .testi-quote {
      font-size: 14px;
      color: #334155;
      line-height: 1.65;
      margin-bottom: 20px;
    }
    .testi-user {
      display: flex;
      align-items: center;
      gap: 12px;
    }
    .testi-avatar {
      width: 42px;
      height: 42px;
      background: #E2E8F0;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      color: var(--primary);
    }
    .testi-name {
      font-size: 14px;
      font-weight: 700;
      color: var(--primary);
    }
    .testi-role {
      font-size: 12px;
      color: var(--text-muted);
    }

    /* 10. 行业资讯摘要 */
    .insights-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .insight-card {
      background: var(--bg-white);
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      padding: 24px;
      box-shadow: var(--shadow-sm);
    }
    .insight-date {
      font-size: 12px;
      color: var(--text-muted);
      margin-bottom: 8px;
    }
    .insight-title {
      font-size: 16px;
      font-weight: 700;
      color: var(--primary);
      margin-bottom: 10px;
      line-height: 1.4;
    }
    .insight-desc {
      font-size: 13px;
      color: var(--text-muted);
      line-height: 1.6;
      margin-bottom: 16px;
    }
    .insight-link {
      font-size: 13px;
      font-weight: 600;
      color: var(--primary-accent);
    }

    /* 11. FAQ 手风琴 */
    .faq-wrapper {
      max-width: 860px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border-color);
    }
    .faq-question {
      padding: 20px 0;
      font-size: 17px;
      font-weight: 600;
      color: var(--primary);
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      user-select: none;
    }
    .faq-icon {
      font-size: 20px;
      font-weight: 400;
      color: var(--text-muted);
      transition: transform 0.2s;
    }
    .faq-answer {
      display: none;
      padding-bottom: 20px;
      font-size: 14px;
      color: #475569;
      line-height: 1.7;
    }
    .faq-item.active .faq-answer {
      display: block;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }

    /* 12. 底部转化驱动区 */
    .contact-card-wrap {
      background: #FFFFFF;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-card);
      overflow: hidden;
    }
    .contact-grid {
      display: grid;
      grid-template-columns: 1.2fr 0.8fr;
    }
    .contact-form-side {
      padding: 40px;
    }
    .contact-info-side {
      background: #F8FAFC;
      border-left: 1px solid var(--border-color);
      padding: 40px;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
    }
    .form-group-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 16px;
      margin-bottom: 16px;
    }
    .form-group {
      margin-bottom: 16px;
    }
    .form-label {
      display: block;
      font-size: 13px;
      font-weight: 600;
      color: var(--primary);
      margin-bottom: 6px;
    }
    .form-input, .form-select {
      width: 100%;
      padding: 10px 12px;
      border: 1px solid #CBD5E1;
      border-radius: var(--radius-sm);
      font-size: 14px;
      color: var(--text-main);
      outline: none;
    }
    .form-input:focus, .form-select:focus {
      border-color: var(--primary-accent);
      box-shadow: 0 0 0 2px rgba(21,128,61,0.1);
    }
    .submit-btn {
      width: 100%;
      padding: 12px;
      background: var(--primary);
      color: #fff;
      font-size: 15px;
      font-weight: 600;
      border: none;
      border-radius: var(--radius-sm);
      cursor: pointer;
    }
    .submit-btn:hover {
      background: #1E293B;
    }
    .sla-badge {
      display: inline-block;
      font-size: 12px;
      font-weight: 600;
      color: var(--primary-accent);
      background: #ECFDF5;
      padding: 4px 10px;
      border-radius: 4px;
      margin-bottom: 16px;
    }

    /* Footer */
    .site-footer {
      background: #080C13;
      color: #94A3B8;
      font-size: 13px;
      padding: 48px 0 24px;
      border-top: 1px solid rgba(255,255,255,0.06);
    }
    .footer-top-grid {
      display: grid;
      grid-template-columns: 1.5fr 1fr 1fr;
      gap: 40px;
      margin-bottom: 36px;
    }
    .footer-brand {
      font-size: 18px;
      font-weight: 700;
      color: #F8FAFC;
      margin-bottom: 12px;
    }
    .footer-desc {
      line-height: 1.6;
      max-width: 380px;
    }
    .footer-links-col h4 {
      font-size: 14px;
      font-weight: 600;
      color: #F8FAFC;
      margin-bottom: 12px;
    }
    .footer-links-col ul {
      list-style: none;
    }
    .footer-links-col li {
      margin-bottom: 8px;
    }
    .footer-links-col a:hover {
      color: #F8FAFC;
    }
    .footer-bottom {
      border-top: 1px solid rgba(255,255,255,0.08);
      padding-top: 24px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      gap: 12px;
    }

    /* Responsive */
    .mobile-menu-btn {
      display: none;
      background: none;
      border: none;
      cursor: pointer;
      padding: 8px;
    }
    .mobile-menu-icon {
      width: 24px;
      height: 2px;
      background: var(--primary);
      position: relative;
    }
    .mobile-menu-icon::before, .mobile-menu-icon::after {
      content: '';
      position: absolute;
      width: 24px;
      height: 2px;
      background: var(--primary);
      left: 0;
    }
    .mobile-menu-icon::before { top: -6px; }
    .mobile-menu-icon::after { bottom: -6px; }

    @media (max-width: 1024px) {
      .challenges-grid { grid-template-columns: repeat(2, 1fr); }
      .advantages-grid { grid-template-columns: repeat(2, 1fr); }
      .metrics-bar { grid-template-columns: repeat(2, 1fr); }
      .solutions-grid { grid-template-columns: 1fr; }
      .arch-grid { grid-template-columns: 1fr; }
      .algo-grid { grid-template-columns: 1fr; }
    }

    @media (max-width: 768px) {
      .top-bar { display: none; }
      .mobile-menu-btn { display: block; }
      .nav-links {
        display: none;
        position: absolute;
        top: 72px;
        left: 0;
        right: 0;
        background: #fff;
        flex-direction: column;
        padding: 24px;
        border-bottom: 1px solid var(--border-color);
        box-shadow: var(--shadow-card);
      }
      .nav-links.active {
        display: flex;
      }
      .hero-grid { grid-template-columns: 1fr; }
      .cases-grid { grid-template-columns: 1fr; }
      .testimonials-grid { grid-template-columns: 1fr; }
      .insights-grid { grid-template-columns: 1fr; }
      .contact-grid { grid-template-columns: 1fr; }
      .contact-info-side { border-left: none; border-top: 1px solid var(--border-color); }
      .footer-top-grid { grid-template-columns: 1fr; }
      .form-group-row { grid-template-columns: 1fr; }
    }

    @media (max-width: 520px) {
      .challenges-grid { grid-template-columns: 1fr; }
      .advantages-grid { grid-template-columns: 1fr; }
      .metrics-bar { grid-template-columns: 1fr; }
      .hero-btn-group { flex-direction: column; }
    }