How to make Html::checkboxList standalone instead of inline?

Question

Yii

I use Html::checkboxList like this:

Html::checkboxList('practice', null, $practice, ['class'=>'checkbox'])

Checkboxes with captions are displayed all in one line as if using .checkbox-inline
How can I force them to be displayed in a column so that the checkbox is under the checkbox?
And then it turns out like this:

Answer 1

Example: codepen.io/kkremen/pen/ZQwNqE
In short:

.checkbox {
    display: block;
}