bootstrap 4 coll padding for sm code example
Example 1: 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>
Example 2: .col-12 bootstrap
.col-12{
flex: 0 0 100%;
max-width: 100%;
}