/* roulang page: index */
/* 自定义设计变量与全局样式 */
    :root {
      --primary-400: #0D9488;
      --primary-500: #0F766E;
      --primary-700: #134E4A;
      --accent-500: #F59E0B;
      --neutral-50: #F8FAFC;
      --neutral-200: #E2E8F0;
      --neutral-400: #64748B;
      --neutral-800: #1E293B;
      --footer-bg: #0F172A;
      --radius-card: 16px;
      --radius-inner: 12px;
      --radius-btn: 999px;
      --shadow-sm: 0 4px 12px rgba(0,0,0,0.04);
      --shadow-md: 0 12px 24px rgba(0,0,0,0.08);
      --transition-smooth: 0.25s ease;
      --font-system: 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', system-ui, -apple-system, 'Segoe UI', sans-serif;
      --font-data: 'Inter', 'PingFang SC', 'Microsoft YaHei', system-ui;
    }
    * {
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-system);
      background-color: #FFFFFF;
      color: var(--neutral-800);
      line-height: 1.6;
      margin: 0;
      padding: 0;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a, button, input, select, textarea {
      font-family: inherit;
    }
    .container {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }
    /* 导航毛玻璃效果 */
    .nav-blur {
      background: rgba(255,255,255,0.85);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid rgba(226, 232, 240, 0.6);
    }
    /* 自定义按钮与渐变 */
    .btn-primary {
      background: linear-gradient(135deg, var(--primary-400), var(--primary-500));
      color: white;
      border-radius: var(--radius-btn);
      padding: 0.75rem 2rem;
      font-weight: 600;
      box-shadow: 0 4px 10px rgba(13, 148, 136, 0.25);
      transition: var(--transition-smooth);
      display: inline-block;
      text-align: center;
    }
    .btn-primary:hover {
      filter: brightness(1.1);
      transform: scale(1.02);
      box-shadow: 0 8px 18px rgba(13, 148, 136, 0.3);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary-500);
      color: var(--primary-700);
      border-radius: var(--radius-btn);
      padding: 0.75rem 2rem;
      font-weight: 600;
      transition: var(--transition-smooth);
      display: inline-block;
      text-align: center;
    }
    .btn-outline:hover {
      background: rgba(13, 148, 136, 0.08);
      border-color: var(--primary-400);
    }
    .card-hover {
      transition: var(--transition-smooth);
      box-shadow: var(--shadow-sm);
    }
    .card-hover:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-md);
    }
    /* 数据徽章微交互 */
    .metric-badge {
      background: rgba(13, 148, 136, 0.04);
      border-radius: var(--radius-inner);
      padding: 1.5rem;
      transition: background 0.2s;
    }
    .metric-badge:hover {
      background: rgba(13, 148, 136, 0.08);
    }
    /* 手风琴动画 */
    details[open] summary .icon-chevron {
      transform: rotate(45deg);
    }
    .icon-chevron {
      transition: transform 0.2s ease;
      display: inline-block;
      font-size: 1.4rem;
      line-height: 1;
    }
    /* 汉堡菜单纯CSS实现 */
    #menu-toggle {
      display: none;
    }
    .mobile-menu {
      display: none;
    }
    @media (max-width: 767px) {
      .desktop-nav-links {
        display: none;
      }
      .mobile-menu {
        display: block;
      }
      #menu-toggle:checked ~ .mobile-nav-panel {
        max-height: 400px;
        opacity: 1;
        pointer-events: auto;
      }
      .mobile-nav-panel {
        max-height: 0;
        opacity: 0;
        overflow: hidden;
        transition: max-height 0.35s ease, opacity 0.25s ease;
        background: white;
        position: absolute;
        top: 72px;
        left: 0;
        width: 100%;
        box-shadow: 0 12px 24px rgba(0,0,0,0.05);
        pointer-events: none;
      }
      .mobile-nav-panel a {
        display: block;
        padding: 1rem 1.5rem;
        border-bottom: 1px solid var(--neutral-200);
        font-weight: 500;
        color: var(--neutral-800);
      }
      .mobile-nav-panel a:hover {
        background: var(--neutral-50);
        color: var(--primary-500);
      }
    }
    /* 巨型面板 hover 效果 (纯CSS) */
    .mega-trigger:hover .mega-panel,
    .mega-trigger:focus-within .mega-panel {
      opacity: 1;
      visibility: visible;
      transform: translateY(0);
      pointer-events: auto;
    }
    .mega-panel {
      position: absolute;
      right: 0;
      top: 100%;
      margin-top: 8px;
      width: 480px;
      background: white;
      border-radius: var(--radius-card);
      box-shadow: 0 20px 30px rgba(0,0,0,0.12);
      padding: 1.5rem;
      opacity: 0;
      visibility: hidden;
      transform: translateY(-8px);
      transition: 0.2s ease;
      pointer-events: none;
      z-index: 50;
      display: flex;
      gap: 1.5rem;
    }
    @media (max-width: 520px) {
      .mega-panel {
        width: 92vw;
        right: -20px;
        flex-direction: column;
      }
    }
    .mega-col {
      flex: 1;
    }
    .mega-card {
      background: var(--neutral-50);
      border-radius: 10px;
      padding: 0.75rem 1rem;
      margin-bottom: 0.75rem;
      transition: 0.15s;
    }
    .mega-card:hover {
      background: #e6f7f5;
    }