/* roulang page: index */
:root {
      --primary: #F04E23;
      --primary-hover: #D13D1A;
      --secondary: #1E3A5F;
      --accent: #00B4D8;
      --accent-hover: #0096B5;
      --bg-light: #F8FAFC;
      --bg-white: #FFFFFF;
      --text-heading: #0F172A;
      --text-body: #334155;
      --text-muted: #64748B;
      --border-light: #E2E8F0;
      --shadow-sm: 0 4px 12px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.08);
      --radius-card: 12px;
      --radius-btn: 8px;
      --font-sans: 'Inter', 'PingFang SC', 'Microsoft YaHei', system-ui, -apple-system, sans-serif;
      --transition: 0.3s ease;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg-light);
      color: var(--text-body);
      line-height: 1.7;
      font-size: 16px;
      display: flex;
      flex-direction: column;
      min-height: 100vh;
    }

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

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

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      transition: var(--transition);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      border: none;
      background: none;
    }

    /* 左侧 App Shell 导航 - 桌面端 */
    .app-nav {
      position: fixed;
      left: 0;
      top: 0;
      width: 80px;
      height: 100vh;
      background-color: var(--secondary);
      display: flex;
      flex-direction: column;
      align-items: center;
      padding: 24px 0;
      z-index: 1000;
      box-shadow: 4px 0 12px rgba(0,0,0,0.06);
    }

    .nav-logo {
      margin-bottom: 40px;
      font-weight: 800;
      font-size: 18px;
      color: white;
      writing-mode: vertical-lr;
      letter-spacing: 2px;
      background: linear-gradient(135deg, var(--primary), #FF8C42);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }

    .nav-menu {
      display: flex;
      flex-direction: column;
      gap: 24px;
      flex: 1;
      align-items: center;
    }

    .nav-item {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 6px;
      color: rgba(255,255,255,0.7);
      font-size: 12px;
      font-weight: 500;
      padding: 8px 12px;
      border-radius: 8px;
      transition: var(--transition);
      position: relative;
      width: 72px;
      text-align: center;
      cursor: pointer;
    }

    .nav-item i {
      font-size: 22px;
      color: inherit;
    }

    .nav-item:hover {
      background-color: rgba(255,255,255,0.1);
      color: white;
    }

    .nav-item.active {
      color: white;
      background-color: rgba(240,78,35,0.2);
    }

    .nav-item.active::before {
      content: '';
      position: absolute;
      left: 0;
      top: 8px;
      bottom: 8px;
      width: 3px;
      background-color: var(--primary);
      border-radius: 0 4px 4px 0;
    }

    .nav-bottom {
      margin-top: auto;
      display: flex;
      flex-direction: column;
      gap: 16px;
      color: rgba(255,255,255,0.6);
    }

    .nav-bottom i {
      font-size: 20px;
      cursor: pointer;
      transition: var(--transition);
    }

    .nav-bottom i:hover {
      color: white;
    }

    /* 移动端汉堡菜单按钮 */
    .mobile-menu-toggle {
      display: none;
      background: none;
      border: none;
      color: var(--secondary);
      font-size: 28px;
      cursor: pointer;
      padding: 8px;
    }

    /* 主内容区域 */
    .main-content {
      margin-left: 80px;
      flex: 1;
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }

    section {
      padding: 100px 0;
    }

    /* Hero */
    .hero {
      display: flex;
      align-items: center;
      min-height: 100vh;
      background-color: var(--bg-white);
      position: relative;
      overflow: hidden;
    }

    .hero-grid {
      display: flex;
      align-items: center;
      gap: 60px;
    }

    .hero-text {
      flex: 1;
    }

    .hero-text h1 {
      font-size: 48px;
      font-weight: 800;
      line-height: 1.2;
      color: var(--secondary);
      margin-bottom: 24px;
    }

    .hero-text .highlight {
      color: var(--primary);
      position: relative;
    }

    .hero-text p {
      font-size: 18px;
      color: var(--text-body);
      margin-bottom: 32px;
      max-width: 500px;
    }

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

    .btn-primary {
      background-color: var(--primary);
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      letter-spacing: 0.5px;
      box-shadow: 0 4px 10px rgba(240,78,35,0.25);
    }

    .btn-primary:hover {
      background-color: var(--primary-hover);
      box-shadow: 0 8px 18px rgba(240,78,35,0.35);
      transform: translateY(-1px);
    }

    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
    }

    .btn-outline:hover {
      background-color: rgba(240,78,35,0.08);
    }

    .hero-image {
      flex: 1;
      border-radius: 24px;
      overflow: hidden;
      box-shadow: var(--shadow-md);
    }

    .hero-image img {
      width: 100%;
      height: auto;
      object-fit: cover;
    }

    /* 通用标题 */
    .section-title {
      font-size: 36px;
      font-weight: 700;
      color: var(--text-heading);
      margin-bottom: 16px;
      line-height: 1.3;
    }

    .section-subtitle {
      color: var(--text-muted);
      font-size: 18px;
      margin-bottom: 48px;
    }

    .text-center {
      text-align: center;
    }

    /* 痛点卡片 */
    .card-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
      gap: 24px;
    }

    .pain-card {
      background: var(--bg-white);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-card);
      padding: 32px 24px;
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
    }

    .pain-card:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-4px);
      border-color: var(--primary);
    }

    .pain-icon {
      font-size: 32px;
      color: var(--accent);
      margin-bottom: 16px;
    }

    .pain-card h3 {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 8px;
      color: var(--text-heading);
    }

    /* 解决方案卡片 */
    .solution-card {
      background: var(--bg-white);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
    }

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

    .solution-img {
      height: 200px;
      object-fit: cover;
    }

    .solution-body {
      padding: 24px;
    }

    .solution-body h3 {
      font-size: 24px;
      font-weight: 600;
      margin-bottom: 12px;
    }

    .feature-list {
      list-style: none;
      margin: 16px 0;
    }

    .feature-list li {
      display: flex;
      align-items: center;
      gap: 8px;
      margin-bottom: 8px;
      font-size: 15px;
    }

    .feature-list i {
      color: var(--accent);
      font-size: 18px;
    }

    .text-link {
      color: var(--accent);
      font-weight: 600;
      border-bottom: 1px dashed var(--accent);
      display: inline-block;
      margin-top: 8px;
    }

    .text-link:hover {
      border-bottom-style: solid;
      color: var(--accent-hover);
    }

    /* 数据展示 */
    .stats-row {
      display: flex;
      justify-content: space-around;
      flex-wrap: wrap;
      gap: 32px;
      background: #F0F4F8;
      border-radius: 24px;
      padding: 48px 24px;
    }

    .stat-item {
      text-align: center;
    }

    .stat-number {
      font-size: 52px;
      font-weight: 800;
      background: linear-gradient(135deg, var(--primary), var(--accent));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }

    .stat-label {
      color: var(--text-muted);
      margin-top: 8px;
    }

    /* 证言 */
    .testimonial-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
      gap: 24px;
    }

    .testimonial-card {
      background: white;
      border-radius: var(--radius-card);
      padding: 24px;
      box-shadow: var(--shadow-sm);
      border-left: 4px solid var(--primary);
    }

    .testimonial-text {
      font-style: italic;
      color: var(--text-body);
      margin-bottom: 20px;
      font-size: 16px;
    }

    .client-info {
      display: flex;
      align-items: center;
      gap: 12px;
    }

    .client-avatar {
      width: 44px;
      height: 44px;
      border-radius: 50%;
      background-color: #ddd;
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
    }

    .faq-question {
      width: 100%;
      background: #F8FAFC;
      padding: 16px 20px;
      font-weight: 600;
      font-size: 18px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      color: var(--text-heading);
      border: none;
      cursor: pointer;
    }

    .faq-answer {
      padding: 0 20px 16px;
      color: #4A5568;
      line-height: 1.8;
      display: none;
    }

    .faq-item.active .faq-answer {
      display: block;
    }

    .faq-item.active .faq-question {
      background: #F0F4F8;
    }

    .arrow-icon {
      transition: transform 0.3s;
    }

    .faq-item.active .arrow-icon {
      transform: rotate(180deg);
    }

    /* CTA */
    .cta-section {
      background: linear-gradient(170deg, #F0F4F8 0%, #FFFFFF 100%);
      text-align: center;
      padding: 100px 0;
    }

    .btn-lg {
      padding: 18px 40px;
      font-size: 18px;
      font-weight: 700;
      margin-top: 24px;
    }

    /* 页脚 */
    .footer {
      background: #1A202C;
      color: #CBD5E0;
      padding: 60px 0 30px;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr;
      gap: 40px;
    }

    .footer h4 {
      color: white;
      margin-bottom: 16px;
      font-weight: 600;
    }

    .footer a {
      color: #CBD5E0;
      display: block;
      margin-bottom: 8px;
    }

    .footer a:hover {
      color: var(--primary);
    }

    .copyright {
      border-top: 1px solid #2D3748;
      margin-top: 40px;
      padding-top: 20px;
      text-align: center;
      font-size: 14px;
    }

    /* 移动端响应式 */
    @media (max-width: 1024px) {
      .app-nav {
        display: none;
      }
      .main-content {
        margin-left: 0;
      }
      .mobile-menu-toggle {
        display: block;
        position: fixed;
        top: 16px;
        left: 16px;
        z-index: 1100;
        background: white;
        border-radius: 8px;
        padding: 8px;
        box-shadow: 0 2px 8px rgba(0,0,0,0.1);
      }
      .mobile-nav {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        background: rgba(30,58,95,0.95);
        backdrop-filter: blur(12px);
        display: flex;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: 32px;
        z-index: 1050;
        transform: translateX(-100%);
        transition: 0.3s;
      }
      .mobile-nav.open {
        transform: translateX(0);
      }
      .mobile-nav a {
        color: white;
        font-size: 24px;
        font-weight: 600;
      }
    }

    @media (max-width: 768px) {
      .hero-grid {
        flex-direction: column;
      }
      .section-title {
        font-size: 28px;
      }
      .stats-row {
        flex-direction: column;
      }
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }