Fusion+Theme+-+CSS+Aggregation

After installing and enabling Fusion and Aggregator, I received the following error message:

Where can I find CSS aggregation or is this another module I need to download and enable?

Hi Maeve, as per the assignment brief, I am not testing the sites in Internet Explorer (I don't even have it, my studio is all Mac) – so you don't need to worry about this. If you were going to put this site into production, you would want to enable CSS aggregation (it can be found in configuration >> performance) as it compresses all the CSS files into a compact, faster-to-read mega-stylesheet. However DO NOT turn this on as it will make Firebug useless and cause many issues if you are still working on your CSS. Essentially, it is something you turn on when your site is totally complete to improve performance. – GJS