OnMouseEnter, change color.

Hello guys. So, I'm just playing around in Unity (god, it's so fun when you know even the tiniest bit of scripting), so I was trying to make a main menu. I usually just go with GUI.Button which is great but this time I wanted to make it different, based OnMouseEnter, so I looked it up, searched a bit, somebody said that I will need to use "OnMouseExit, OnMouseDown" and so, which is like GetButtonDown, I think , at least for me.

Anyways, here is the script.

 public class mainMenu : MonoBehaviour {
 
     void OnMouseEnter ()
     {
         renderer.material.color = Color.red;
     }
 
     void OnMouseExit ()
     {
         renderer.material.color = Color.black;
     }
 
     void OnMouseDown ()
     {
         Application.LoadLevel (1);
     }
 
 
 }
 Now, there is nothing wrong with the code, true but when my mouse gets on the 3D Text, the color is not changing, why?

Yes, there is a collider with the box "On Trigger" checked.