Hi hunnsdon,
Currently, we are stuck with more work.
So we can’t make it responsive now.
But if you want responsive, i will suggest you PRO version of this plugin..
http://www.wpfruits.com/notification-bar-pro/
In PRO version you can add unlimited notification bars and can use different notification bar for every post and page.
And except this there are so many features are included in PRO version.
You can look over the PRO version features using given below link..
http://www.wpfruits.com/notification-bar-pro/
Hope it would be helpful to you.
Best!
Nishant