Styles vs Styles: TwentyTwelve

Hi,

I have the ‘Styles’ plugin installed and it seems to work fine with the Twenty Twelve theme. Recently I have been getting a message saying:

“Styles is almost ready! To add theme options for Twenty Twelve, please install Styles: Twenty Twelve.”

Does this mean I need to install the ‘Styles: TwentyTwelve’ plugin as well as the ‘Styles’ plugin?

What’s the difference between them?

Thanks!