/* roulang page: index */
/* 基础重置与设计变量 */
    :root {
      --primary: #0A2E1F;
      --primary-hover: #164B33;
      --accent: #E85D04;
      --accent-hover: #C94D00;
      --bg-warm: #F7F5F0;
      --bg-white: #FFFFFF;
      --bg-dark: #0A2E1F;
      --bg-highlight: #EDF5F0;
      --text-primary: #1A1A1A;
      --text-secondary: #5C5C5C;
      --text-on-dark: #FFFFFF;
      --text-on-dark-muted: #B0C7BB;
      --border-light: #E0DCD3;
      --border-card: rgba(0,0,0,0.04);
      --shadow-card: 0 2px 16px rgba(0,0,0,0.04), 0 0 0 1px rgba(0,0,0,0.03);
      --shadow-hover: 0 8px 30px rgba(0,0,0,0.08);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 8px;
      --font-stack: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Noto Sans SC", system-ui, sans-serif;
      --transition-smooth: 0.3s ease;
      --transition-fast: 0.2s ease;
    }
    
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    
    body {
      font-family: var(--font-stack);
      background-color: var(--bg-warm);
      color: var(--text-primary);
      line-height: 1.8;
      font-size: 16px;
      font-weight: 400;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }
    
    img {
      max-width: 100%;
      height: auto;
      display: block;
      border-radius: 8px;
    }
    
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition-fast);
    }
    
    button, input, textarea {
      font-family: var(--font-stack);
      outline: none;
      border: none;
    }
    
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 32px;
    }
    
    /* 排版体系 */
    h1 {
      font-size: 48px;
      font-weight: 700;
      line-height: 1.2;
      letter-spacing: -0.5px;
      color: var(--text-primary);
    }
    
    h2 {
      font-size: 36px;
      font-weight: 600;
      line-height: 1.3;
      letter-spacing: -0.3px;
      margin-bottom: 48px;
      color: var(--text-primary);
    }
    
    h3 {
      font-size: 22px;
      font-weight: 600;
      line-height: 1.4;
      margin-bottom: 16px;
      color: var(--text-primary);
    }
    
    .text-lg {
      font-size: 18px;
      line-height: 1.8;
      color: var(--text-secondary);
    }
    
    .text-sm {
      font-size: 14px;
      line-height: 1.6;
      color: var(--text-secondary);
    }
    
    /* 导航结构 */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid transparent;
      transition: box-shadow 0.25s ease, border-color 0.25s ease;
      padding: 0 32px;
    }
    
    .site-header.scrolled {
      box-shadow: 0 4px 20px rgba(0,0,0,0.04);
      border-bottom: 1px solid var(--border-light);
    }
    
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
      max-width: 1280px;
      margin: 0 auto;
    }
    
    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 700;
      font-size: 24px;
      color: var(--primary);
      letter-spacing: -0.5px;
    }
    
    .logo i {
      font-size: 28px;
      color: var(--accent);
    }
    
    .nav-links {
      display: flex;
      align-items: center;
      gap: 40px;
    }
    
    .nav-links a {
      font-weight: 500;
      font-size: 16px;
      color: var(--text-primary);
      position: relative;
      padding: 8px 0;
    }
    
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent);
      transition: width 0.25s ease;
    }
    
    .nav-links a:hover::after,
    .nav-links a.active::after {
      width: 100%;
    }
    
    .btn-accent {
      background: var(--accent);
      color: white;
      font-weight: 600;
      font-size: 16px;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      letter-spacing: 0.5px;
      transition: background var(--transition-fast), transform var(--transition-fast);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      cursor: pointer;
      border: none;
    }
    
    .btn-accent:hover {
      background: var(--accent-hover);
      transform: scale(1.02);
    }
    
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      font-weight: 600;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      transition: background var(--transition-fast), color var(--transition-fast), transform var(--transition-fast);
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      justify-content: center;
    }
    
    .btn-outline:hover {
      background: rgba(10,46,31,0.1);
      transform: scale(1.02);
    }
    
    .mobile-menu-toggle {
      display: none;
      background: none;
      border: none;
      font-size: 24px;
      color: var(--primary);
    }
    
    /* 区块通用 */
    .section {
      padding: 100px 0;
    }
    
    @media (max-width: 1023px) {
      .section {
        padding: 80px 0;
      }
      h1 {
        font-size: 40px;
      }
      h2 {
        font-size: 30px;
      }
    }
    
    @media (max-width: 767px) {
      .section {
        padding: 60px 0;
      }
      h1 {
        font-size: 32px;
      }
      h2 {
        font-size: 26px;
        margin-bottom: 32px;
      }
      h3 {
        font-size: 20px;
      }
      .container {
        padding: 0 20px;
      }
      .nav-links {
        display: none;
      }
      .mobile-menu-toggle {
        display: block;
      }
      .site-header {
        padding: 0 20px;
      }
      .nav-container {
        height: 64px;
      }
      /* 移动端底部导航作为备用，但保留汉堡菜单交互，这里简化处理：使用隐藏的移动菜单样式在JS中控制 */
      .mobile-nav-open .nav-links {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 72px;
        left: 0;
        width: 100%;
        background: white;
        padding: 24px;
        box-shadow: 0 12px 30px rgba(0,0,0,0.05);
        gap: 20px;
      }
    }
    
    /* Hero 双栏 */
    .hero-grid {
      display: grid;
      grid-template-columns: 55% 45%;
      gap: 40px;
      align-items: center;
    }
    
    .hero-left {
      display: flex;
      flex-direction: column;
      gap: 24px;
    }
    
    .hero-left h1 {
      margin-bottom: 0;
    }
    
    .hero-subtitle {
      font-size: 18px;
      color: var(--text-secondary);
      max-width: 480px;
    }
    
    .hero-actions {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
      margin-top: 8px;
    }
    
    .hero-right {
      position: relative;
      border-radius: 16px;
      overflow: hidden;
      height: 480px;
    }
    
    .hero-right img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      border-radius: 16px;
    }
    
    .hero-overlay {
      position: absolute;
      inset: 0;
      background: rgba(10,46,31,0.12);
      pointer-events: none;
    }
    
    @media (max-width: 1023px) {
      .hero-grid {
        grid-template-columns: 1fr;
        gap: 32px;
      }
      .hero-right {
        height: 360px;
        order: -1;
      }
    }
    
    /* 优势网格 */
    .advantages-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px;
    }
    
    .adv-item {
      background: transparent;
      padding: 24px 0;
      border-bottom: 1px solid var(--border-light);
      transition: border-color 0.2s ease;
    }
    
    .adv-item:hover {
      border-bottom-color: var(--primary);
    }
    
    .adv-icon {
      font-size: 48px;
      color: var(--primary);
      margin-bottom: 20px;
      display: inline-block;
    }
    
    .adv-item h3 {
      margin-bottom: 8px;
    }
    
    @media (max-width: 1023px) {
      .advantages-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 24px;
      }
    }
    
    @media (max-width: 767px) {
      .advantages-grid {
        grid-template-columns: 1fr;
      }
    }
    
    /* 案例瀑布流 */
    .case-item {
      display: grid;
      grid-template-columns: 1fr 1.2fr;
      gap: 40px;
      align-items: center;
      margin-bottom: 80px;
    }
    
    .case-item.reverse {
      grid-template-columns: 1.2fr 1fr;
    }
    
    .case-item.reverse .case-img {
      order: 1;
    }
    
    .case-img img {
      width: 100%;
      height: 320px;
      object-fit: cover;
      border-radius: 12px;
      box-shadow: var(--shadow-card);
    }
    
    .case-content {
      display: flex;
      flex-direction: column;
      gap: 16px;
    }
    
    .case-tag {
      display: inline-block;
      background: var(--bg-highlight);
      color: var(--primary);
      padding: 4px 14px;
      border-radius: 20px;
      font-size: 14px;
      font-weight: 500;
    }
    
    .case-stat {
      font-size: 32px;
      font-weight: 700;
      color: var(--accent);
    }
    
    @media (max-width: 1023px) {
      .case-item, .case-item.reverse {
        grid-template-columns: 1fr;
        gap: 24px;
      }
      .case-item.reverse .case-img {
        order: 0;
      }
      .case-img img {
        height: 260px;
      }
    }
    
    /* 对比表 */
    .compare-table-wrapper {
      overflow-x: auto;
      border-radius: 12px;
      background: white;
      box-shadow: var(--shadow-card);
    }
    
    .compare-table {
      width: 100%;
      border-collapse: collapse;
      min-width: 700px;
    }
    
    .compare-table th {
      background: var(--bg-warm);
      padding: 20px 24px;
      font-weight: 600;
      font-size: 16px;
      text-align: left;
    }
    
    .compare-table td {
      padding: 20px 24px;
      border-bottom: 1px solid var(--border-light);
      font-size: 16px;
    }
    
    .compare-table .highlight-col {
      background: var(--bg-highlight);
      font-weight: 600;
    }
    
    .metric-up {
      color: var(--accent);
      font-weight: 700;
    }
    
    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 20px 0;
    }
    
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      font-weight: 600;
      font-size: 20px;
    }
    
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease, padding 0.2s ease;
      color: var(--text-secondary);
      line-height: 1.8;
      padding-right: 40px;
    }
    
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-top: 12px;
    }
    
    .faq-icon {
      color: var(--accent);
      font-size: 20px;
    }
    
    /* CTA 区域 */
    .cta-section {
      background: var(--bg-dark);
      color: white;
      padding: 80px 0;
    }
    
    .cta-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: start;
    }
    
    .cta-left h2 {
      color: white;
      margin-bottom: 16px;
    }
    
    .contact-form input, .contact-form textarea {
      width: 100%;
      padding: 14px 18px;
      border-radius: var(--radius-input);
      background: white;
      border: 1px solid var(--border-light);
      margin-bottom: 16px;
      font-size: 16px;
    }
    
    .contact-form button {
      width: 100%;
    }
    
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1.5fr;
      gap: 40px;
      margin-top: 48px;
      padding-top: 48px;
      border-top: 1px solid rgba(255,255,255,0.15);
    }
    
    .footer-col p, .footer-col i {
      color: var(--text-on-dark-muted);
    }
    
    .copyright {
      text-align: center;
      padding: 24px 0;
      background: #051810;
      color: var(--text-on-dark-muted);
      font-size: 14px;
    }
    
    @media (max-width: 767px) {
      .cta-grid, .footer-grid {
        grid-template-columns: 1fr;
        gap: 32px;
      }
    }