The popup or middle-page in the Magento extension has a standard design, that you might want to change, to streamline it with your webshop.
First, these files handle the HTML of the page and popup respectively:
These files can be changed, and new classes can be added if necessary, to change the styling of individual parts:
The extension also has a specific CSS file that can be modified:
This file allows you to add and modify CSS specifically for the extension: