Customize Survey Pop-up Layout

Hi there,

We're looking to change the layout of the pop-up which appears when we ask a customer to participate in our forum survey. We've implemented a test survey into stage and would like to change the layout of this pop-up. I was wondering if this is possible?

We have managed to change the text string so the pop-up does now say what we want it to. We feel this pop-up that appears is too large and we would like it to be a little smaller. Is there any way we can change the default size of the pop-up and also the positioning of the buttons? I have looked through the CSS and had no luck. Can anyone point in the correct direction as to where this specific element can be changed within studio?

I have attached the pop-up that we would like to edit. This pop-up appears when a registered user makes a forum post or an anonymous user navigates away from out forum.

Thanks.