How to apply new css styles to all page templates?

Hi

I find that if I make changes, like font styles, using WP's customizer the new styles are applied only to a particular page template like "home" page. The new styles are not applied to "single post" or other "page" templates.

Is there a way to ensure the new styles are applied to other page templates?

Or is there a way to copy "all the CSS of new changes" made so that I may paste them on the style.css manually?

Thank you!