How can the user customize Dashboard in kibana 7.5?

I want to cutomize Kibana Dasboard from the Kibana UI i.e. change font size,colours or the panel borders. Is there any way of doing it in Kibana version 7.5 ?

You can change the source code in Kibana, i think the details like these are in the .less files.

Can you tell me the location and the name of these .less files which could help me change the font size, background colours or the border style of the panels on the dashboard?