@instantflorian i just released a new version of the module Accordion.
This version fixes the problems on a smaller screen with big titles.
Some extra css fixes to polish the module.
Added an extra option to choose on which side you want the icon +/- (left or right).
Demo and download over here: http://nibz.nl/module/accordion/
Hope everything works for you.
If you have any questions don't hessitate to ask!
If you have additional wishes let me know