/* roulang page: index */
/* ----- 设计变量与基础重置 ----- */
    :root {
      --primary-slate: #1A2F3B;
      --accent-coral: #FF6B5B;
      --accent-coral-hover: #E55A4A;
      --bg-warm-white: #F7F5F2;
      --bg-card: #FFFFFF;
      --bg-section-alt: #F0EDE8;
      --text-heading: #0F1E26;
      --text-body: #4A5568;
      --text-muted: #8A94A6;
      --data-amber: #F5A623;
      --shadow-sm: 0 2px 12px rgba(26, 47, 59, 0.06);
      --shadow-md: 0 8px 24px rgba(26, 47, 59, 0.12);
      --radius-card: 12px;
      --radius-btn: 8px;
      --font-heading: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --font-body: "PingFang SC", "Noto Sans SC", "Segoe UI", sans-serif;
      --font-mono: "SF Mono", "Menlo", "Consolas", monospace;
      --container-max: 1200px;
      --nav-height: 64px;
    }

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

    html {
      scroll-behavior: smooth;
    }

    body {
      font-family: var(--font-body);
      background-color: var(--bg-warm-white);
      color: var(--text-body);
      line-height: 1.8;
      -webkit-font-smoothing: antialiased;
    }

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

    a {
      color: inherit;
      text-decoration: none;
    }

    button, input {
      font-family: inherit;
      outline: none;
      border: none;
    }

    /* ----- 容器与通用布局 ----- */
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }

    @media (max-width: 640px) {
      .container {
        padding: 0 16px;
      }
    }

    /* ----- 导航组件 (固定顶部，居中Logo) ----- */
    .main-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--nav-height);
      background-color: rgba(26, 47, 59, 0.92);
      backdrop-filter: blur(8px);
      z-index: 1000;
      box-shadow: 0 1px 8px rgba(0,0,0,0.1);
    }

    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 100%;
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }

    .nav-left, .nav-right {
      display: flex;
      align-items: center;
      gap: 28px;
    }

    .nav-link {
      color: #E0E5E9;
      font-weight: 500;
      font-size: 0.95rem;
      position: relative;
      padding: 4px 2px;
      transition: color 0.2s;
    }

    .nav-link::after {
      content: "";
      position: absolute;
      bottom: -2px;
      left: 50%;
      transform: translateX(-50%) scaleX(0);
      width: 100%;
      height: 2px;
      background-color: var(--accent-coral);
      transition: transform 0.25s ease;
    }

    .nav-link:hover {
      color: var(--accent-coral);
    }

    .nav-link:hover::after {
      transform: translateX(-50%) scaleX(1);
    }

    .logo-center {
      font-family: var(--font-heading);
      font-weight: 800;
      font-size: 1.8rem;
      color: white;
      letter-spacing: 2px;
      display: flex;
      align-items: center;
      gap: 4px;
    }

    .logo-center i {
      color: var(--accent-coral);
      font-size: 1.6rem;
    }

    .mobile-menu-btn {
      display: none;
      background: transparent;
      color: white;
      font-size: 1.8rem;
      cursor: pointer;
    }

    @media (max-width: 1024px) {
      .nav-left, .nav-right {
        display: none;
      }
      .mobile-menu-btn {
        display: block;
        margin-left: auto;
      }
      .nav-container {
        justify-content: space-between;
      }
      .logo-center {
        order: -1;
      }
    }

    /* 移动端菜单面板 */
    .mobile-panel {
      position: fixed;
      top: 0;
      right: 0;
      width: 75%;
      max-width: 320px;
      height: 100vh;
      background-color: var(--primary-slate);
      z-index: 1100;
      transform: translateX(100%);
      transition: transform 0.35s ease;
      padding: 32px 24px;
      display: flex;
      flex-direction: column;
      gap: 28px;
      box-shadow: -4px 0 20px rgba(0,0,0,0.25);
    }

    .mobile-panel.active {
      transform: translateX(0);
    }

    .mobile-panel a {
      color: #E0E5E9;
      font-size: 1.2rem;
      border-bottom: 1px solid rgba(255,255,255,0.15);
      padding-bottom: 12px;
    }

    .mobile-panel .close-btn {
      align-self: flex-end;
      background: transparent;
      color: white;
      font-size: 2rem;
      cursor: pointer;
    }

    /* ----- 板块通用间距 ----- */
    section {
      padding: 100px 0;
    }

    @media (max-width: 768px) {
      section {
        padding: 70px 0;
      }
    }

    /* ----- Hero 首屏 (背景图叠加) ----- */
    .hero {
      position: relative;
      min-height: 100vh;
      display: flex;
      align-items: center;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      background-attachment: fixed;
      margin-top: 64px;
    }

    .hero-overlay {
      position: absolute;
      inset: 0;
      background: linear-gradient(135deg, rgba(26,47,59,0.8) 0%, rgba(15,30,38,0.7) 100%);
    }

    .hero-content {
      position: relative;
      z-index: 2;
      width: 100%;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 40px;
    }

    .hero-text {
      flex: 1;
      max-width: 600px;
    }

    .hero h1 {
      font-family: var(--font-heading);
      font-size: 3.6rem;
      font-weight: 800;
      color: white;
      line-height: 1.3;
      margin-bottom: 24px;
    }

    .hero h1 span {
      color: var(--accent-coral);
    }

    .hero-sub {
      font-size: 1.2rem;
      color: rgba(255,255,255,0.85);
      margin-bottom: 40px;
      max-width: 500px;
    }

    .hero-actions {
      display: flex;
      flex-wrap: wrap;
      gap: 16px;
    }

    .btn {
      display: inline-block;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 1rem;
      transition: all 0.25s ease;
      cursor: pointer;
      text-align: center;
    }

    .btn-primary {
      background-color: var(--accent-coral);
      color: white;
      border: 2px solid var(--accent-coral);
    }

    .btn-primary:hover {
      background-color: var(--accent-coral-hover);
      border-color: var(--accent-coral-hover);
      transform: scale(1.03);
      box-shadow: 0 8px 18px rgba(255,107,91,0.3);
    }

    .btn-outline {
      background: transparent;
      color: var(--accent-coral);
      border: 2px solid var(--accent-coral);
    }

    .btn-outline:hover {
      background: rgba(255,107,91,0.08);
      transform: translateY(-2px);
    }

    .hero-stats {
      flex: 0 0 280px;
      display: flex;
      flex-direction: column;
      gap: 24px;
      background: rgba(255,255,255,0.08);
      backdrop-filter: blur(10px);
      padding: 30px;
      border-radius: 16px;
    }

    .stat-item h3 {
      font-family: var(--font-mono);
      font-size: 2.6rem;
      color: var(--data-amber);
      font-weight: 800;
    }

    .stat-item p {
      color: rgba(255,255,255,0.7);
      font-size: 0.9rem;
    }

    @media (max-width: 900px) {
      .hero-content {
        flex-direction: column;
        text-align: center;
      }
      .hero h1 {
        font-size: 2.5rem;
      }
      .hero-stats {
        flex-direction: row;
        flex-wrap: wrap;
        justify-content: center;
        width: 100%;
      }
    }

    /* ----- 实时指标看板 ----- */
    .dashboard-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
      margin-top: 20px;
    }

    .metric-card {
      background: var(--bg-card);
      border-radius: var(--radius-card);
      padding: 28px 20px;
      box-shadow: var(--shadow-sm);
      transition: box-shadow 0.3s;
    }

    .metric-card:hover {
      box-shadow: var(--shadow-md);
    }

    .metric-number {
      font-family: var(--font-mono);
      font-size: 2.8rem;
      font-weight: 800;
      color: var(--data-amber);
      display: flex;
      align-items: baseline;
      gap: 6px;
    }

    .metric-label {
      color: var(--text-body);
      margin: 8px 0 12px;
    }

    .trend-bars {
      display: flex;
      gap: 4px;
      align-items: flex-end;
      height: 28px;
    }

    .bar {
      width: 6px;
      background: linear-gradient(to top, var(--accent-coral), #ffa090);
      border-radius: 2px;
      transition: height 0.3s;
    }

    @media (max-width: 900px) {
      .dashboard-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }

    /* ----- 服务矩阵 (左侧竖线风格) ----- */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 30px;
      margin-top: 40px;
    }

    .service-card {
      background: var(--bg-card);
      border-radius: var(--radius-card);
      padding: 28px 24px;
      box-shadow: var(--shadow-sm);
      border-left: 4px solid var(--accent-coral);
      transition: all 0.3s ease;
      display: flex;
      flex-direction: column;
    }

    .service-card:hover {
      border-left-width: 8px;
      box-shadow: var(--shadow-md);
      background: #FFFCFA;
    }

    .service-img {
      height: 120px;
      background-size: cover;
      background-position: center;
      border-radius: 8px;
      margin-bottom: 20px;
    }

    .service-card h3 {
      font-family: var(--font-heading);
      color: var(--text-heading);
      margin-bottom: 10px;
    }

    .service-desc {
      color: var(--text-body);
      margin-bottom: 18px;
      flex: 1;
    }

    .perf-tag {
      font-weight: 700;
      color: var(--accent-coral);
      font-size: 0.9rem;
      display: flex;
      align-items: center;
      gap: 6px;
    }

    @media (max-width: 900px) {
      .services-grid {
        grid-template-columns: 1fr;
      }
    }

    /* ----- 对比组件 ----- */
    .comparison-wrapper {
      display: flex;
      gap: 30px;
      margin-top: 40px;
    }

    .compare-col {
      flex: 1;
      padding: 32px;
      border-radius: 16px;
    }

    .compare-before {
      background: #E9E5E0;
      color: #4A4A4A;
    }

    .compare-after {
      background: white;
      border: 2px solid var(--accent-coral);
    }

    .compare-col h3 {
      margin-bottom: 16px;
    }

    .metric-red {
      color: #C0392B;
      font-weight: 700;
    }

    .metric-green {
      color: #27AE60;
      font-weight: 700;
    }

    @media (max-width: 700px) {
      .comparison-wrapper {
        flex-direction: column;
      }
    }

    /* ----- 技术架构流程 ----- */
    .arch-flow {
      display: flex;
      justify-content: space-between;
      align-items: center;
      margin-top: 40px;
      flex-wrap: wrap;
    }

    .arch-step {
      text-align: center;
      flex: 1;
      padding: 20px;
    }

    .arch-icon {
      font-size: 2.4rem;
      color: var(--accent-coral);
      margin-bottom: 12px;
    }

    /* ----- FAQ 手风琴 ----- */
    .faq-list {
      margin-top: 30px;
      display: flex;
      flex-direction: column;
      gap: 16px;
    }

    .faq-item {
      background: white;
      border-radius: 12px;
      box-shadow: var(--shadow-sm);
      padding: 20px 24px;
      cursor: pointer;
      transition: 0.2s;
    }

    .faq-question {
      display: flex;
      align-items: center;
      gap: 12px;
      font-weight: 700;
      color: var(--text-heading);
    }

    .faq-dot {
      width: 10px;
      height: 10px;
      background: var(--accent-coral);
      border-radius: 50%;
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: var(--text-body);
      padding-left: 22px;
      margin-top: 8px;
    }

    .faq-item.active .faq-answer {
      max-height: 200px;
    }

    /* ----- CTA 全幅 ----- */
    .cta-section {
      background-color: var(--primary-slate);
      text-align: center;
      color: white;
    }

    .cta-form {
      display: flex;
      max-width: 500px;
      margin: 30px auto 0;
      gap: 12px;
      flex-wrap: wrap;
      justify-content: center;
    }

    .cta-input {
      flex: 1;
      padding: 14px 18px;
      border-radius: 30px;
      background: white;
    }

    /* ----- 页脚 ----- */
    .footer {
      background: #0F1E26;
      color: #B0BEC5;
      padding: 60px 0 20px;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 30px;
    }

    .footer-col h4 {
      color: white;
      margin-bottom: 16px;
    }

    .footer-col a {
      display: block;
      color: #B0BEC5;
      margin-bottom: 8px;
      transition: 0.2s;
    }

    .footer-col a:hover {
      color: var(--accent-coral);
    }

    .copyright {
      text-align: center;
      margin-top: 40px;
      border-top: 1px solid #2C3E47;
      padding-top: 20px;
    }

    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }