body {
      display: flex;
      flex-direction: column;
      align-items: center;
      background: #f4f4f9;
      font-family: Arial, sans-serif;
      margin: 0;
      padding: 20px;
    }
    h1 {
      margin-bottom: 20px;
    }
    #bars {
      display: flex;
      align-items: flex-end;
      height: 300px;
      width: 80%;
      border: 1px solid #ccc;
      margin: 20px 0;
      background: #fff;
      padding: 5px;
    }
    .bar {
      flex: 1;
      margin: 0 2px;
      background: #4caf50;
      transition: 0.3s all;
    }
    .bar.active {
      background: #ff5722;
    }
    .controls {
      display: flex;
      gap: 10px;
    }
    button, select {
      padding: 8px 12px;
      font-size: 14px;
      border: none;
      border-radius: 5px;
      cursor: pointer;
      background: #6200ea;
      color: white;
    }
    button:hover, select:hover {
      opacity: 0.9;
    }