fileInput "Browse..." button style

How to set a style (bootstrap) for the fileInput "Browse…" button?

<?= $form->field($model, ‘file’)->fileInput([‘value’ => $model->logo_link, ‘class’ =>‘btn btn-primary’]) ?>

this way changes area around the button.

The "browse file" button in bootstrap is not styled automatically.

You should either user a file upload widget (i.e. https://packagist.org/packages/2amigos/yii2-file-upload-widget or for a list https://packagist.org/search/?q=yii2%20file%20upload) or style it yourself http://stackoverflow.com/questions/11235206/twitter-bootstrap-form-file-element-upload-button.