Could you please put the CSS in a separate file, thus not in the html? Or maybe not include it at all, then we can add the CSS ourselves to the existing style.css file? This would be great as it will minimize code bloat (which is helpful in making a site search engine friendly), plus it makes it easier to control.
Recently, I started using your plugin and wanted to make it style seamlessly with my client's design. Unfortunately though, in order to do so, I had change the CSS in your plugin code, which of course was later overwritten when I updated the plugin with the latest version. So, instead of having to redo my CSS every time, it would be great if it were in a separate file like the majority of the other plugins, or again, not included at all. This would be most helpful, and consequently, I'd start using and advocating Mail Chimp again.