Are plugins loaded as modules or themes

I’m trying to create a plugin for micro.blog.

Currently, I’m working on it locally and don’t know how I would test it in micro.blog without having it as the theme.

I’m trying to figure out the CSS styling at this point, do I include it in the assets for the plugin, hard code the style in the html output, include it in my theme, or rely on the custom css of the user.

To sum it up, I would like to know the order in which the css is loaded.

I figured it out. The interface for testing themes is the same for plugins.

I just didn’t remember it was there or maybe it’s been there and I never had a reason to look.