bootstrap 4 d-flex content-justify code example

Example 1: bootstrap justify-content-center for md

<div class="row justify-content-md-center"></div>

Example 2: Bootstrap 4 Flex

<div class="d-flex p-3 bg-secondary text-white">
  <div class="p-2 bg-info">Flex item 1</div>
  <div class="p-2 bg-warning">Flex item 2</div>
  <div class="p-2 bg-primary">Flex item 3</div>
</div>