Firefox can't load a website properly. Troubleshooting doesn't help.

For some reason the website 'Tumblr' (http://tumblr.com) won't display correctly in Firefox no matter what I do. It displays as it should in other browsers and other computers with Firefox. Here is what I've tried: - Followed all steps on Mozilla's troubleshooting page -Deleted browsing history/cleared cache -Removed all add-ons -Disabled plug-ins -Opened in safe mode -Deleted and reinstalled the program -Disabled hardware acceleration -Updated Windows Nothing seems to fix the issue.