Adjust width content sidebar

I added a translate-widget in my sidebar by Trevor Creech yesterday on my website.

Every time I want to install a non-standard widgets in my theme the content is too big. I started with this theme (Ocadia by Beccary) more than two years ago and adapted it to my wishes, so bare with me as I do not want to switch. I’ve looked into the solutions on this forum, but to no avail. I’m looking for a solution that can fix this problem knowing that it might just be a flimsy workaround.

What file do I adjust? Can I add code to my style.css or is there something simple piece of code I can insert in the translate widget that will allow me to make the content smaller?