hello, please try the steps given at Websites look wrong or appear differently than they should

Hi madperson, thanks. I did try all of that before posting this. Nothing works. What is strange is that not whole site is rendering incorrectly. Header and sidebar are ok, just search results are wrong.

hallo, have you also tried to launch firefox in safemode once - maybe one of your addons is interfering?

Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

although i don't think it's related, you could also try updating your nvidia graphics driver ...

Everything is the same in safe mode with add-ons disabled. Now I also noticed the whole wikipedia is rendering improperly. see It's like the page is zoomed in, but it's not.

Also, it doesn't happen in other browsers, so it's rather some firefox settings that I changed that doesn't work well with new update.

You can rename the content-prefs.sqlite file to content-prefs.sqlite.old (or delete the file) in the Profile Folder to reset the page zoom on all sites.

• http://kb.mozillazine.org/Profile_folder_-_Firefox

You can use this button to go to the Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Open Containing Folder

After trying everything I reset Firefox and problem is solved. Thanks everyone for help.