ExtJS FileUpload Button height

HTML

<script src="https://cdn.sencha.com/ext/gpl/4.2.1/ext-all-debug-w-comments.js"></script>
<link rel="stylesheet" href="https://cdn.sencha.com/ext/gpl/4.2.1/resources/css/ext-all.css">

CSS

#zoom {
  background: grey;
  /* IE 9 */
  -ms-transform-origin: 0 0;
  -ms-transform: scale(2);
  /* Safari */
  -webkit-transform-origin: 0 0;
  -webkit-transform: scale(2);
  transform-origin: 0 0;
  transform: scale(2);
}

.browseBtnCls {
  padding: 0px !important;
  background-color: transparent !important;
  border-color: transparent;
  width: 0px
}

JavaScript

Ext.application({
  name: 'MyApp',
  launch: function() {
    Ext.create('Ext.form.Panel', {
      title: 'Upload a File',
      width: 400,
      bodyPadding: 10,
      frame: true,
      renderTo: Ext.getBody(),
      items: [{
        xtype: 'filefield',
        name: 'photo',
        fieldLabel: 'Upload a file',
        emptyText: 'Click here to browse files...',
        labelWidth: 100,
        msgTarget: 'side',
        allowBlank: false,
        anchor: '100%',
        buttonText: '',
        buttonConfig: {
          cls: 'browseBtnCls'
        }
      }],
    });
  }
});