Well, There is some issues with negative margins and structure. I made couple videos to show you more correct method to manage elements. You can fallow my steps for fix overlap problems:
https://drive.google.com/file/d/0B-7cg8BSq1Z_X2ZHYnZJMlZNR28/view?usp=drivesdk
https://drive.google.com/file/d/0B-7cg8BSq1Z_YnVUVzF5ZmZCVWM/view?usp=drivesdk
Or just rough method- make div “NewWorkshop” overflow=hidden, on all devices. It should fix the problem, but will notice again: using negative margins for manage elements positioning is not good practice and better use this methods when nothing else can be done.
Regards,
Anna