After I install Microsoft fonts, facebook font for the Persian content changes to Arial, which is a very bad font for Persian. This happens in both Chrome and Firefox. Here's the font family used by facebook: 'lucida grande',tahoma,verdana,arial,sans-serif
The problem is: for English content, Verdana is selected, which is the right choice. But for Persian content, Arial is given first priority - that means if I remove Arial from the list, everything will be okay (Verdana is used).
If I uninstall Microsoft fonts, hence getting rid of Arial, sans-serif is used which makes things better, at the expense of changing font for English content as well.
Any ideas what is going on?