legend.itemStyle doesn't seem to be accepting a Highcharts.CSSObject. When trying to apply:
legend: {
itemStyle: {
color: "#5f5e5e",
fontFamily: "Roboto",
fontSize: "12px"
}
},
I get this error:
value ({'color': '#5f5e5e', 'fontFamily': 'Roboto', 'fontSize': '12px'}) was not coerced to a string