body {
    font-family: sans-serif;
  }
  .bar {
    opacity: 0.8;
    transition: opacity 0.3s;
  }
  .bar:hover {
    opacity: 1;
  }
  .axis-label {
    font-size: 14px;
    font-weight: bold;
  }
  .tooltip {
    position: absolute;
    padding: 6px;
    background: #fff;
    border: 1px solid #ccc;
    border-radius: 5px;
    box-shadow: 0px 2px 8px rgba(0,0,0,0.2);
    font-size: 12px;
    pointer-events: none;
    opacity: 0;
    transition: all 0.3s ease;
  }
  .controls {
    margin-bottom: 20px;
  }
  select {
    margin-right: 10px;
    padding: 5px;
  }
  button {
    margin: 5px;
    padding: 8px 12px;
    font-size: 14px;
    cursor: pointer;
    background-color: #4E79A7;
    color: white;
    border: none;
    border-radius: 4px;
  }
  button:hover {
    background-color: #3a5f8c;
  }
  .legend {
    margin-top: 20px;
  } 
  .legend-item {
    display: inline-block;
    margin-right: 20px;
    font-size: 14px;
  }
  .legend-color {
    width: 12px;
    height: 12px;
    display: inline-block;
    margin-right: 5px;
    vertical-align: middle;
  }
  #loading {
    font-size: 18px;
    text-align: center;
    margin: 20px;
  }
  .hidden {
    display: none;
  }