unity gui style color button
#if UNITY_EDITOR
[CustomEditor(typeof(MyClass))]
public class MyClassEditor : Editor
{
public override void OnInspectorGUI()
{
DrawDefaultInspector();
var style = new GUIStyle(GUI.skin.button);
style.normal.textColor = Color.red;
MyClass c = (MyClass)target;
if (GUILayout.Button("Button Name", style))
{
c.MyMethod();
}
}
}
#endif