CSS changes not showing on vendor sites

Hi All.

I have FrameMarket installed with a Gridmarket child theme.
When I make changes to the styling of the Gridmarket (Either via the built in theme-styles, or directly in CSS), the changes doesn't take effect on vendor sites that I have already created. But if I create another new one, this site will then inherit the changes that I made. Is there a way that I can make changes throughout all the sites. i.e. if I wanted to change the height and/or color of the header bar..

Hope it makes sense..

Thank you :slight_smile: