The short answer is No.
The long answer is Yes, but you’re limited. You can adjust the window by changing the code (trivantis-dialog.js I believe) provided within your Lectora output. The changes we recommend are minimal and don’t match what you described. Doing any more could cause some serious issues with your course.
Better than using the default option is to create a customized pop-up window! These allow for style changes and additional content to be displayed, as well as, being able to adjust the background, size, and location. It’s just a page put at the end of your course that you customize the look and feel of. Then when selecting your feedback options you choose to go to that page but in a new window. Additional window properties which are updatable are available from there.