Resize data points with highcharts

Question

We are using highcharts and are trying to customize a chart to look similar to this:

We were able to set colors as documented and also increase the thickness of the lines by using the lineWidth attribute, but can't find a way to customize the data points so they are always circles and larger than the thicker lines. This is what it looks like at this point:

Also, we can't find a way to remove the default gray horizontal lines.

Help!

Answer 1

This gray line is called grid line, you can customize them following the reference.

To remove grid lines

 yAxis: {
     gridLineWidth: 0
 }

Like this example.

Change marker width

plotOptions: {
    series: {
        marker: {
            enabled: true,
            symbol: 'circle',
            radius: 7
        }
    }
}

demo

You can take a look here if you want to customize series markers.