Helper Classes in Bootstrap

<!-- Ratios -->
<div class="ratio ratio-1x1">1:1</div>
<div class="ratio ratio-4x3">4:3</div>
<div class="ratio ratio-16x9">16:9</div>
<div class="ratio ratio-21x9">21:9</div>

<!-- Stretched Link -->
<div class="card">
  <div class="card-body">
    <h5 class="card-title">
      <a href="#" class="stretched-link">Card link</a>
    </h5>
    <p class="card-text">Entire card is clickable</p>
  </div>
</div>

<!-- Text Truncation -->
<div class="text-truncate" style="width: 150px;">
  This text will truncate with ellipsis
</div>