/* roulang page: index */
/* 自定义CSS变量与深度定制，超越默认Tailwind */
    :root {
      --primary: #0D7377;
      --primary-dark: #0A5C60;
      --accent: #F96D00;
      --accent-dark: #E05D00;
      --text-dark: #1E1E1E;
      --text-muted: #6B7280;
      --bg-light: #F3F4F6;
      --bg-white: #FFFFFF;
      --bg-footer: #1A1A1A;
      --border-light: #E5E7EB;
      --radius-card: 12px;
      --radius-btn: 6px;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
      --shadow-hover: 0 8px 24px rgba(13,115,119,0.12);
      --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Inter', system-ui, -apple-system, sans-serif;
    }

    * {
      box-sizing: border-box;
    }

    body {
      font-family: var(--font-sans);
      color: var(--text-dark);
      background-color: #fff;
      line-height: 1.6;
      margin: 0;
      -webkit-font-smoothing: antialiased;
    }

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

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

    button, .btn {
      cursor: pointer;
      font-family: inherit;
    }

    /* 导航沉浸式效果 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      transition: background-color 0.3s ease, backdrop-filter 0.3s ease, box-shadow 0.3s ease;
      background-color: transparent;
      backdrop-filter: blur(0px);
    }
    .navbar.scrolled {
      background-color: rgba(13, 115, 119, 0.95);
      backdrop-filter: blur(12px);
      box-shadow: 0 4px 20px rgba(0,0,0,0.1);
    }
    .nav-link {
      color: white;
      font-weight: 500;
      position: relative;
      transition: color 0.2s;
    }
    .nav-link:hover, .nav-link.active {
      color: #F96D00;
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0%;
      height: 2px;
      background: #F96D00;
      transition: width 0.2s ease;
    }
    .nav-link:hover::after, .nav-link.active::after {
      width: 100%;
    }

    /* 移动端菜单 */
    .mobile-menu {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: rgba(13, 115, 119, 0.98);
      backdrop-filter: blur(12px);
      flex-direction: column;
      justify-content: center;
      align-items: center;
      z-index: 999;
      opacity: 0;
      pointer-events: none;
      transition: opacity 0.3s ease;
    }
    .mobile-menu.open {
      display: flex;
      opacity: 1;
      pointer-events: auto;
    }

    /* 按钮系统 */
    .btn-primary {
      background-color: var(--accent);
      color: white;
      border-radius: var(--radius-btn);
      padding: 14px 32px;
      font-weight: 600;
      border: none;
      transition: background 0.2s, transform 0.1s;
      display: inline-block;
    }
    .btn-primary:hover {
      background-color: var(--accent-dark);
      transform: scale(1.03);
    }
    .btn-secondary {
      background: transparent;
      color: white;
      border: 2px solid white;
      border-radius: var(--radius-btn);
      padding: 14px 32px;
      font-weight: 600;
      transition: all 0.2s;
    }
    .btn-secondary:hover {
      background: rgba(255,255,255,0.15);
    }
    .btn-outline-dark {
      background: transparent;
      border: 1px solid var(--primary);
      color: var(--primary);
      border-radius: var(--radius-btn);
      padding: 10px 24px;
      font-weight: 600;
    }
    .btn-outline-dark:hover {
      background: rgba(13,115,119,0.05);
    }

    /* 卡片样式 */
    .feature-card {
      background: white;
      border-radius: var(--radius-card);
      padding: 28px 20px;
      box-shadow: var(--shadow-sm);
      transition: transform 0.25s, box-shadow 0.25s, border-color 0.2s;
      border: 1px solid transparent;
    }
    .feature-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
      border-color: var(--primary);
    }
    .pricing-card {
      background: white;
      border-radius: var(--radius-card);
      padding: 32px 24px;
      border: 1px solid var(--border-light);
      transition: all 0.2s;
    }
    .pricing-card.featured {
      border: 2px solid var(--accent);
      transform: scale(1.03);
      box-shadow: 0 0 0 2px rgba(249,109,0,0.2), 0 12px 28px rgba(0,0,0,0.08);
    }

    /* FAQ手风琴 */
    .faq-item {
      background: white;
      border-radius: 8px;
      margin-bottom: 12px;
      overflow: hidden;
    }
    .faq-question {
      padding: 16px 24px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      background: white;
      transition: background 0.2s;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s ease;
      background: #F9FAFB;
      padding: 0 24px;
      color: var(--text-muted);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding: 16px 24px;
    }
    .faq-icon {
      transition: transform 0.3s;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }

    /* 数字滚动动画简单示意 */
    .count-up {
      font-weight: 700;
      color: white;
    }

    @media (max-width: 768px) {
      .desktop-nav {
        display: none;
      }
      .mobile-toggle {
        display: block;
      }
    }
    @media (min-width: 769px) {
      .mobile-toggle {
        display: none;
      }
    }