.chart-container {
        position: relative;
        width: 100%;
        max-width: 600px;
        margin-left: auto;
        margin-right: auto;
        height: 300px;
        max-height: 400px;
      }
      @media (min-width: 768px) {
        .chart-container {
          height: 350px;
        }
      }
      .nav-link::after {
        content: '';
        display: block;
        width: 0;
        height: 2px;
        background: #2563eb;
        transition: width 0.3s;
      }
      .nav-link:hover::after, .nav-link.active::after {
        width: 100%;
      }
      .timeline-connector {
        position: absolute;
        top: 20px;
        left: 50%;
        width: calc(100% - 4rem);
        height: 4px;
        background-color: #d1d5db;
        transform: translateX(-50%);
        z-index: 0;
      }
      @media (max-width: 767px) {
        .timeline-connector {
            left: 20px;
            top: 50%;
            width: 4px;
            height: calc(100% - 4rem);
            transform: translateY(-50%);
        }
      }
      /* Placeholder styling */
      .img-placeholder {
          background-color: #f3f4f6;
          border: 2px dashed #cbd5e1;
          display: flex;
          flex-direction: column;
          align-items: center;
          justify-content: center;
          overflow: hidden;
          margin: 0 auto;
      }