/* roulang page: index */
/* 自定义 CSS 变量与全局样式 */
    :root {
      --primary-green: #0A8F3C;
      --deep-gray: #1E1E1E;
      --accent-lime: #B8F200;
      --bg-warm: #F7F5F0;
      --card-white: #FFFFFF;
      --text-primary: #2C2C2C;
      --text-secondary: #6B6B6B;
      --text-on-dark: #FFFFFF;
      --border-light: #E5E7EB;
      --shadow-sm: 0 4px 20px rgba(0,0,0,0.06);
      --shadow-md: 0 8px 30px rgba(0,0,0,0.12);
      --radius-card: 12px;
      --radius-btn: 8px;
      --transition-base: 0.3s ease;
    }

    * {
      box-sizing: border-box;
    }

    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      margin: 0;
      padding: 0;
      background-color: var(--bg-warm);
      color: var(--text-primary);
      line-height: 1.75;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

    .container {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 24px;
      padding-right: 24px;
    }

    @media (max-width: 767px) {
      .container {
        padding-left: 16px;
        padding-right: 16px;
      }
    }

    /* 导航栏毛玻璃效果 */
    .nav-glass {
      background: rgba(255,255,255,0.95);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid rgba(0,0,0,0.05);
      transition: box-shadow 0.3s ease;
    }
    .nav-scrolled {
      box-shadow: 0 4px 20px rgba(0,0,0,0.06);
    }

    /* 导航链接下划线指示器 */
    .nav-link {
      position: relative;
      color: var(--text-primary);
      font-weight: 500;
      transition: color 0.2s;
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0;
      height: 2px;
      background-color: var(--accent-lime);
      transition: width 0.25s ease;
    }
    .nav-link:hover {
      color: var(--primary-green);
    }
    .nav-link:hover::after {
      width: 100%;
    }

    /* 按钮样式 */
    .btn-primary {
      background-color: var(--accent-lime);
      color: var(--deep-gray);
      font-weight: 600;
      border-radius: var(--radius-btn);
      padding: 14px 32px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: background-color 0.2s, transform 0.2s;
      border: none;
      cursor: pointer;
      text-decoration: none;
      letter-spacing: 0.3px;
    }
    .btn-primary:hover {
      background-color: #A3D600;
      transform: scale(1.03);
    }

    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary-green);
      color: var(--primary-green);
      font-weight: 600;
      border-radius: var(--radius-btn);
      padding: 12px 30px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: all 0.25s;
      cursor: pointer;
      text-decoration: none;
    }
    .btn-outline:hover {
      background-color: var(--primary-green);
      color: white;
      border-color: var(--primary-green);
    }

    /* 卡片通用样式 */
    .card {
      background: var(--card-white);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      transition: transform 0.3s ease, box-shadow 0.3s ease;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }

    /* 亮点网格图标容器 */
    .icon-circle {
      width: 64px;
      height: 64px;
      background-color: var(--primary-green);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-size: 28px;
      transition: background-color 0.3s;
    }
    .card:hover .icon-circle {
      background-color: var(--accent-lime);
      color: var(--deep-gray);
    }

    /* 案例瀑布流卡片图片缩放 */
    .case-card img {
      transition: transform 0.4s ease;
    }
    .case-card:hover img {
      transform: scale(1.03);
    }

    /* FAQ 手风琴动画 */
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease, padding 0.35s ease;
      background-color: #F3F4F6;
      border-left: 3px solid var(--primary-green);
      border-radius: 0 8px 8px 0;
    }
    .faq-item.active .faq-answer {
      max-height: 300px;
      padding: 16px 20px;
      margin-top: 8px;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }
    .faq-icon {
      transition: transform 0.3s ease;
      font-size: 20px;
      color: var(--primary-green);
    }

    /* 表单焦点发光 */
    input:focus, textarea:focus {
      outline: none;
      border-color: var(--primary-green);
      box-shadow: 0 0 0 3px rgba(184, 242, 0, 0.3);
    }

    /* 汉堡菜单全屏面板 */
    .mobile-menu {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: rgba(255,255,255,0.98);
      backdrop-filter: blur(16px);
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      transform: translateY(-100%);
      transition: transform 0.4s cubic-bezier(0.23, 1, 0.32, 1);
      z-index: 50;
    }
    .mobile-menu.open {
      transform: translateY(0);
    }