yii2 gridview：如何为filterModel配置css

I want to config form text for 'filterModel'. Here's my code.

GridView::widget([
    'dataProvider' => $dataProvider,
    'filterModel' => $searchModel,
    'columns' => $gridColumns,
])

Here is some options of GridzView for filterModel. GridView api

/**
 * @var array the HTML attributes for the filter row element.
 * @see \yii\helpers\Html::renderTagAttributes() for details on how attributes are being rendered.
 */
public $filterRowOptions = ['class' => 'filters'];
/**
 * @var array the options for rendering the filter error summary.
 * Please refer to [[Html::errorSummary()]] for more details about how to specify the options.
 * @see renderErrors()
 */
public $filterErrorSummaryOptions = ['class' => 'error-summary'];
/**
 * @var array the options for rendering every filter error message.
 * This is mainly used by [[Html::error()]] when rendering an error message next to every filter input field.
 */
public $filterErrorOptions = ['class' => 'help-block'];