window.addEvent('domready', function(){
 elems = $$('#gruponav a');
 
 origSize=elems[0].getStyle('font-size').toInt();
 extraSize=origSize * 1.25;
      
 elems.addEvents({
  'mouseover': function(){
    this.set('tween',{duration: 'short'}).tween('font-size',extraSize + "px");
  },
  'mouseout' : function(){
    this.set('tween',{duration: 'short'}).tween('font-size',origSize + "px");
  }
 });
});