.kpi-card {
    transition: transform 0.2s, box-shadow 0.2s;
  }

  .kpi-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
  }

  .chart-container {
    position: relative;
    height: 280px;
    width: 100%;
  }

  .period-btn.active {
    background: var(--primary-color);
    color: white;
  }