/* roulang page: index */
:root {
      --primary-color: #0f766e;
      --accent-color: #10b981;
      --bg-base: #f8fafc;
      --text-main: #0f172a;
      --text-muted: #64748b;
      --border-color: #e2e8f0;
    }
    body {
      font-family: system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      background-color: var(--bg-base);
      color: var(--text-main);
      overflow-x: hidden;
      line-height: 1.65;
    }
    .hero-bg-overlay {
      background: linear-gradient(105deg, rgba(15, 23, 42, 0.94) 0%, rgba(15, 118, 110, 0.82) 55%, rgba(15, 23, 42, 0.88) 100%);
    }
    .metric-num {
      font-feature-settings: "tnum";
      font-variant-numeric: tabular-nums;
    }
    .accordion-content {
      transition: max-height 0.3s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.25s ease;
    }
    .accordion-item.active .accordion-content {
      max-height: 320px;
      opacity: 1;
    }
    .accordion-item.active .accordion-icon {
      transform: rotate(180deg);
    }