Cyrillic/Russian text doesn't see in WebGL build

Unity Engine
1

For example simple code:

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

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!

2