Firefox 3.5 doesn’t allow @font-face to reference a font that is hosted on a remote server, although Safari does. Firefox simply doesn’t show the font and uses the next font in the font stack. In order to use @font-face on a blog like Tumblr, the .htaccess file on your server that hosts the font file needs to be edited to allow the blog to use the font.
Edit your server .htaccess file. Add the following to limit the use of your font files to only your Tumblr blogs:<FilesMatch "\.(eot|ttf|otf)$"> <IfModule mod_headers.c> Header set Access-Control-Allow-Origin: http://yourblog.tumblr.com Header set Access-Control-Allow-Origin: http://yourblog2.tumblr.com </IfModule> </FilesMatch>