fontSize for Total in donut chart

[ghost]

Hi

I want to show a fixed value inside the donut.

                                total: {
                                    show: true,                                    
                                    showAlways: true,
                                    label: 'week',
                                    color: '#373d3f',
                                    formatter: function (w) {
                                        return "";
                                    }
                                }                                                                

This is working ok but I don't have control over the font size so I see it like this:

Also, I expect it to appear in the middle, how is it possible?

[junedchhipa]

Added fontSize & fontFamily to the total label.