I managed to fix the address bar problem, now I just need help with the borders

From what you say it seems to be your theme. A similar issue was reported in the thread linked here. https://support.mozilla.org/en-US/questions/1371945

From what you say it seems to be your theme. A similar issue was reported in the thread linked here. https://support.mozilla.org/en-US/questions/1371945

This doesn't seem to be the same problem. It doesn't affect the website, just adds these annoying borders. It's not caused by themes, and actually changes color dependent on the theme, so it must be something with Firefox.

Where is the image in your second screenshot from if not a website? I am pasting some links relating to troubleshooting and profiles. A quick way to test your profile is to create a new profile. You do not need to configure it unless it solves the problem.

Your culprit may be hardware acceleration (see the third link) unless you have enabled "resist fingerprinting" which can also cause issues.

https://support.mozilla.org/en-US/kb/troubleshoot-and-diagnose-firefox-problems https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

https://support.mozilla.org/en-US/kb/firefox-protection-against-fingerprinting

Where is the image in your second screenshot from if not a website? I am pasting some links relating to troubleshooting and profiles. A quick way to test your profile is to create a new profile. You do not need to configure it unless it solves the problem. Your culprit may be hardware acceleration (see the third link) unless you have enabled "resist fingerprinting" which can also cause issues. https://support.mozilla.org/en-US/kb/troubleshoot-and-diagnose-firefox-problems https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data https://support.mozilla.org/en-US/kb/firefox-protection-against-fingerprinting

The problem isn't the theme, something I did in about:config caused it but I do not remember what. It does not happen in another profile. Resist fingerprinting was enabled, but when disabled did not fix the problem. Disabling hardware acceleration did not fix it either.

I still have this border problem, and a new problem has occured out of thin air as well. When I attempt to play a roblox game all that occurs is this error that shows up immediately after clicking play. I haven't changed any settings recently, and would like recommendations on what about:config setting may have caused this. It works perfectly fine in other profiles, but not in my default profile's containers. I'm 100% sure it's something with my profile.

I managed to fix the problem by refreshing my Firefox. It appears my resolution was spoofed, but I dunno why roblox wasn't working. All good now.