Apple makes it's own drivers and updates, and they are included in OS updates. It's not like Windows where you have to check for the latest driver version all the time in order to get an app to work properly. Unless you are using something you installed yourself.
Safari might not trust the website's use of WebGL, so that might be the reason for the message, but you can change that in the settings. As Havok mentioned though, it won't matter because C3 only runs in Chrome anyway.
If you need to enable WebGL in Chrome, here are some instructions:
http://ccm.net/faq/40585-how-to-enable- ... gle-chrome