You really are using a whole slew of things that HTML mail clients flat out don't support properly if at all... things like the STYLE attribute... You cannot rely on it and should not use it.
With HMTL e-mails you basicially have to dial the clock back to 1997 and pretend anything newer than HTML 3.2 does not exist. That means NO CSS -- at all. Even if a handful of mail clients attempt to support it, the simple fact is support is partial at best, an unreliable mess at worst.
NOT that I believe in sending HTML e-mails in the first place, or if I did send them I'd send multi-encoded so there's a plaintext version too, since HTML e-mails are often used as a spam filter since there's no legitimate reason for 'real' e-mails to even have HTML in them; you can pretty much assume if it's an HTML mail, it's spam.
Oh, BTW, you do know mediafire blocks hotlinking, right?