Delicacy Pro "responsive design" definition

This might be a question for the theme designer, but I have the free delicacy theme and am considering upgrading to pro. I’m not sure what all is included in responsive design. I know I can choose more colors and there is a footer. But I’m wondering if I will be able to fill the header with my logo rather than just a small side area as shown. Plus, I haven’t done a lot of (if any) changes to CSS on my current template. Do I need to worry about having a parent theme to just switch over to delicacy pro?

https://gooddinnermom.com

Thank you