Highcharts Demo

author(s): Torstein Hønsi

HTML

<script src="https://code.highcharts.com/highcharts.js"></script>

<div id="container" style="height: 400px"></div>

CSS

.highcharts-tooltip-box {
  fill: red;
}

JavaScript

$(function() {
  Highcharts.wrap(Highcharts.Tooltip.prototype, 'renderSplit', function(p, labels, points) {
    p.call(this, labels, points);

    var tt = this.tt;

    if (tt) {
      tt.attr({
        padding: 15,
        fill: 'red',
        stroke: 'blue',
        'stroke-width': 3,
        r: 10
      });
      
      tt.text.attr({
        y: 45
      })
    }
  });

  Highcharts.chart('container', {
    xAxis: {
      categories: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'],
      tickmarkPlacement: 'on',
      labels: {
        style: {
          color: 'red'
        }
      }
    },

    tooltip: {
      split: true,
      headerFormat: '<span style="font-size: 30px; color: white">{point.key}</span>'
    },

    series: [{
      data: [29.9, 71.5, 106.4, 129.2, 144.0, 176.0, 135.6, 148.5, 216.4, 194.1, 95.6, 54.4]
    }, {
      data: [89.9, 21.5, 126.4, 149.2, 14.0, 76.0, 35.6, 48.5, 26.4, 14.1, 98.6, 94.4]
    }]
  });
});