EDIT: I found the problem already and was able to remove the issue myself!
I have a small issue with my main page drop down menu. After playing with some code to make the navigation bigger (which worked totally fine in the end), I have an unwanted % line in my drop down menu. It only appears when you open the shop in full screen, not on mobile. I'm using the debut theme. I hope someone can point me to the code line that is probably causing this issue and how to remove it without butchering the entire thing
Thanks in advance for your help!