Problem with visulization of DateRangePicker

I used some DateRangePicker to set date range for searching date; all appears in this way:

As you see text is under icon and cancel button ‘x’ is not well defined; what am I doing wrong?
Thanks

it is not possible to answer unless you publish how did you implement it - show your PHP / HTML / CSS code. Did you follow properly installation instructions ?

I inherited the application and i’m trying to improve it. I’m sorry, but I’m still learning.
The form with widget:

use yii\helpers\Html;
use yii\widgets\ActiveForm;
use kartik\icons\FontAwesomeAsset;
use kartik\daterange\DateRangePicker;

FontAwesomeAsset::register($this);

        echo '<label class="control-label">Timestamp range</label>';
        echo '<div class="drp-container">';
        echo DateRangePicker::widget([
            'model' => $model,
            'attribute' => 'timestamp',
            'presetDropdown' => true,
            'convertFormat'=>true,
            'options' => ['placeholder' => 'Select timestamp range'],
            'pluginOptions'=> [
                    'locale' => ['format' => 'Y-m-d'],
                ],
        ]);
        echo '</div><div class="help-block"></div>';

I read and try something, but the widget is ever like photo.
Do you think i have to repeat installation ?

Thanks

I found that the widget DateRangePicker i was using has this defect in nature, (see Krajee DateRange), so I updated to Bootstrap 4 and now it’s pretty good.
If someone will have the same problem …