bootstrap class for display flex justifycontent center code example
Example 1: align items center bootstrap
<div class="d-flex align-items-start">...</div>
<div class="d-flex align-items-end">...</div>
<div class="d-flex align-items-center">...</div>
<div class="d-flex align-items-baseline">...</div>
<div class="d-flex align-items-stretch">...</div>
Example 2: bootstrap justify-content-center for md
<div class="row justify-content-md-center"></div>