How do i change the text color on GUI.Label ?

I tried to make style.font.material.color = Color.white; i want the text to be display in white. But i'm getting null exception on this line.

 void OnGUI()
         {
             if (lookatsky == true) 
             {
                 GUIStyle style = new GUIStyle();
                 style.fontSize = 70;
                 style.font.material.color = Color.white;
                 var w1 = 150;
                 var h1 = 150;
                 Rect rect = new Rect((Screen.width-150)/2, (Screen.height-150)/2 + 100, w1, h1);
                 GUI.Label (rect, "The sky is full of spaceships wow this is great", style); 
             }
         }