anchor.diff:      getShadowRoot("media-bar").applyAuthorStyles = true;
   
       toggleSoundButton = $["toggleSound"];
  +    toggleSoundImage = toggleSoundButton.children.first;
       volumeSlider = new RangeSlider($["volumeSlider"]);
       stream = $["audioElement"];
   
  
positive.code:   RangeSlider volumeSlider;
    bool isPlaying;
    AudioElement stream;
  
    MediaBar.created()
      : super.created() {
  
negative.code: 
  
    void toggleSound(Event e) {
      if(isPlaying) {
        pause();
      }
      else {
        play();
      }
    }
  
    void play() {
      toggleSoundImage.src = "img/rest.svg";
      isPlaying = true;
      setVolume(volumeSlider.value);
    }
  
    void pause() {
      toggleSoundImage.src = "img/note.svg";
      isPlaying = false;
      setVolume(0.0);
    }
  
    void setVolume(double vol) {
  