Multiple Gutenberg editor widths

I want to have different Gutenberg editor widths depending on the page/post template. For example I have a full-width page template that is wider than the default page with sidebar.

It seems like I can only use:

.wp-block { width:..; }

If I add a selector before wp-block it doesn’t change the width at all.

Any ideas on how to implement multiple editor widths?

Thank you!