Bootstrap class: .flex-fill

<div class="d-flex text-white">
  <div class="p-2 flex-fill bg-primary">Flex item</div>
  <div class="p-2 flex-fill bg-success">Flex item</div>
  <div class="p-2 flex-fill bg-primary">Flex item</div>
</div>

Preview

Flex item

Flex item

Flex item

Tips 💡

You don't need to remember all CSS classes. Just use the Bootstrap Editor instead.

More in Bootstrap Flexbox

Bootstrap 4 & 5