How To Disable The Use Of Styles In The Configuration File For Yii2 Datepicker?

Yii 2.0 General Discussions
1

Colleagues, this situation: In (Yii2) ActiveForm use widget Jui DatePicker:


<label class="field">

<span class="field__el">

    <?=

    $form->field($model, 'birth_date')->widget(

        DatePicker::className(),

        [

            'language' => 'ru',

            'clientOptions' => [

                'dateFormat' => 'yy-mm-dd'

            ]

        ]

    ) ?>

</span>

</label>

But bad luck, he displayed incorrectly.

All due to the fact that at this widget overlap other styles, in order to fix it must be disabled in the configuration file "main.php" Use this widget styles as specified? Or at least where it is described in the API?