The default font is configured in the Theme Settings > Typography. Hower colors are configured in the Theme Setting > Styles and colors.
You can set the custom fonts in the Advanced Typography, which allows to choose the item from a drop-down or insert your custom CSS class. Please navigate to the Theme Settings > Typography > Advanced Typography.
I added a rule for ‘Main navigation links’ that indeed changes color and color on hover for navigation menu.
The issue I am facing is that ‘My account links in the header’ added in rule does not reflect changes in font color for ‘My Account’ link in the heaader.
Could you please inform me which font advanced typography would change ‘My Account’ link in the header?
Please provide your site URL so that we could provide you with custom CSS. If your site is under maintenance, please provide your site admin access in the private area