The look of my browser Is off Reinstalling does not help What else can I do

Recentty reset my computer and reinstalled Firefox For some reason the look was off so I went to edit it And ever since the a Firefox has been very defective I will try to post a screenshot to share with you. I have uninstall and reinstalled and that did not fix the problem Still the same issue When trying to apply a new theme those themes won't apply. Refresh Firefox to see if the new thing would apply and no it did not. I don't wanna reset my computer just to get Firefox working again. I'm debating Using Revo Uninstaller to fully uninstall Firefox and registry Just see if that will fix it but I will wait to see what you guys say. Firefox is my first choice when it comes to browsers. I can still use it I just don't like the look of it right now I only blame myself. Sorry for the solid paragraph I'm using speech to text my left side paradise from traumatic brain injury and neuropathy.

All I want instigate Firefox to a default look how do I go about that. I'm very good with computers so as long as you explain to me I will know how to do it. Thank you.