Easily clear floats by adding .clearfix to the parent element. Can also be used as a mixin.

<div class="clearfix">...</div>

The following example shows how the clearfix can be used. Without the clearfix the wrapping div would not span around the buttons which would cause a broken layout.

<div class="bg-primary progress-bar-striped clearfix">
  <button class="btn btn-secondary float-start" type="button">Example Button floated left</button>
  <button class="btn btn-secondary float-end" type="button">Example Button floated right</button>
</div>