bootstrap class for inline block code example
Example 1: bootstrap display inline block
<div class="d-inline-block"></div>
Example 2: bootstrap display block
<div class="d-block"></div>
d-block = for displaying
d-none = to hide
Example 3: bootstrap hide row
<div class="d-none"></div> for bootstrap 4
Example 4: is display-block a class
<span class="d-block p-2 bg-primary text-white">d-block</span>
<span class="d-block p-2 bg-dark text-white">d-block</span>