I started a game (with the black pieces) where I have the possibilty to play the Grünfeld that I never played before.
1.d4 Nf6 2.c4 g6 3.Nc3 d5
I want to know what's the main idea behind it, especially for black, since I heard that it could lead to sharp positions and complications (even Kasparov had a hard time playing it against Karpov)