bootstrap columns sytem code example
Example 1: bootstrap col-md-5 center
<div class="container">
<div class="row">
<div class="col-sm-5 mx-auto">
Centered
</div>
</div>
</div>
Example 2: no-gutter bootstrap 4
<div class="row no-gutters">
<div class="col-12 col-sm-6 col-md-8">.col-12 .col-sm-6 .col-md-8</div>
<div class="col-6 col-md-4">.col-6 .col-md-4</div>
</div>