As I'm introducing Google fonts into my emails, I have discovered that they don't work on a few of the Outlooks. That's fine. The problem is that the fallbacks don't work either. They just display as a plain serif.

I import the Google font in the head:

@import url(,700);

Then place in it inline:

<span style="font-family: 'Open Sans', Arial, sans-serif;">Text</span>

So, why would it not fall back to Arial or sans-serif?