bootstrap 4 col vertical centered code example
Example 1: bootstrap column vertical align
<span class="align-baseline">baseline</span>
<span class="align-top">top</span>
<span class="align-middle">middle</span>
<span class="align-bottom">bottom</span>
<span class="align-text-top">text-top</span>
<span class="align-text-bottom">text-bottom</span>
Example 2: how to center vertically in bootstrap col
<div class="my-auto">
...inner divs and content...
</div>