Buying on PC and Mac

[Sureshot]

We don't support cross-platform purchases between Steam and Mac, there's no function on the stores for us to do that.

[r0r0]

Hey,

I've been an avid ICC gamer for more than 10 years now, and have bought every version of the game. Now, however, I'm in a conundrum. I travel a lot and so I played on Mac traditionally (because I take a MacBook Pro on my travels), bu I got a gaming PC last year and I want to switch to that. However, I still want the game on my Mac for when I travel. Would I have to pay for both or is it possible for me to pay once and have it available on both devices? If I have to pay for both I will likely have to pass on Mac and play exclusively on PC...

Thanks!