line_chart_tooltip_style

    div.tooltip {
      position: absolute;
      text-align: center;
      width: 90px;
      height: 32px;
      padding: 2px;
      font: 12px sans-serif;
      background: lightsteelblue;
      border: 0px;
      border-radius: 4px;
      pointer-events: none;
    }