Hello,

If you are referring to the tooltips, I would suggest you to create a tooltip template for the chart series. Tooltip templates can be defined in HTML script tags of the “text/x-jquery-tmpl” type or can be just strings with HTML markup. Tooltips essentially define HTML markup with parameters that is to be rendered on screen. Values to be substituted are defined with the jQuery templating syntax, e.g. ${item.Price}. For example:

    <script id="tooltipTemplate" type="text/x-jquery-tmpl">

        <div id="tooltip" class="ui-widget-content ui-corner-all">       

           <div><span id="tooltipName">${item.Name}</span></div>

           <div><span id="tooltipValue">${item.Price}</span></div>

        </div>

    </script>

Then you can style the tooltips' font and other visual properties using CSS. 

And when defining the series, set the tooltipTemplate option: 

series: [{

    tooltipTemplate: “tooltipTemplate”

    …

}] 

Please let me know if you have any further questions.