Cyrillic/Russian text doesn't see in WebGL build

For example simple code:

Code (CSharp):

1. void OnGUI () {
2.         GUI.Button (new Rect (50,50,100,100), "Я фиксированная кнопка с текстом");
3.    
4.         GUILayout.Button ("Я просто кнопка с текстом");
5.     }

In Editor everything looks fine, but in WebGL build, I didn't see my text at all.
Looking forward in any information on how to fix it in GUILayout items!