button will change color if a mouse hovers it

Hi, i want to make my button to be to change its bg color when a mouse hovers it. Before a put a gui style on it, the hover is okay but after putting a a gui style, button doesnt seem to react when you hover the mouse on it. here is my code: if(showGUI == true)

 {

     GUI.Box(Rect(0,0,screenW/6,screenH/4),"");

     if(GUI.Button(Rect(0,50,200,30),"START",myStyle))

      {
          DontDestroyOnLoad(GameObject.FindWithTag("TIGER"));

          //levelCounter.level1=false;

         load = true;
  }

there is some options in the inspector that i can change the hover,normal and focused but it doesn work.. can you help me ?thanks } if(GUI.Button(Rect(0,80,200,30),"load",myStyle)){

  if(saveLoad.showSaved==true){

     saveLoad.showSaved=false;}

 else if(saveLoad.showSaved==false){

     saveLoad.showSaved=true;
 }    }