Hi Gaurav,
Yes, I thought it might be a little tricky to set a pie chart default via CSS because of the issues you've pointed out. If you would still like to investigate highlighting via CSS, you might find it easier to implement by replacing the pie chart with a bar chart. In general, this is recommended as a better visualization option than a pie chart as it allows a clear and more direct comparison of values.
Regards,
Mustafa.
