[H] TvZ vs Vipers

I'd have to admit I'm not the best player in the world, but how do you engage viper compositions??!?

Also, I'm a mech player generally if that helps. Me and Bio don't mix well DX

I tried spreading my tanks, but that didn't go so well...esp since half my tanks were immobile...

I tried building vikings, but they only managed to kill a few vipers before the rest of my army was clouded up.

I tried widowmines, but they seem to get eaten up before they can do much DX please help !!