master/artweb/artbox-core/views/seo/index.php

<?php
    use yii\bootstrap\Html;
    use yiister\gentelella\widgets\Panel;
    
    $xPanel = Panel::begin();
?>
    <div class="jumbotron" style="min-height: 400px">
        <h1>To be done!</h1>
        <p>...</p>
        <p><?php echo Html::a(
                'Back to main',
                [ '/site/index' ],
                [
                    'class' => 'btn btn-primary btn-lg',
                    'role'  => 'button',
                ]
            ); ?></p>
    </div>
<?php
    $xPanel::end();