I find the K2 content module displays differently between K2 and non-K2 pages.

I have a website that includes Sobi2, EventList and K2. I want to display a K2 content module on all pages (even those of Sobi2 and EventList) but having installed and enable this module, I have found it displays differently between K2 and non-K2 pages. It seems that on K2 pages, it picks up the CSS from my K2 template bit it fails to do this on non-K2 pages. Instead the default CSS is applied to the module.

What's the best solution to overcome this?