Hi,
Welcome to our forum & thanks for the question!
Take a look at this CSS-based
solution:
https://jsfiddle.net/BlackLabel/h4bk1qx9/
If it does not satisfy you, I see two other possible solutions:
1. write a custom loading function so that when
chart.loading your custom components show on top of the chart (your loading animation that covers the chart
2. find a function in
Highcharts.src.js that renders the
chart.loading label and modify the rendered label to something that you want with
H.wrap()
Let me know if that helps!
Best regards,
Jakub