De kolommen worden automatisch op elkaar gestapeld wanneer het scherm minder dan 576px breed is.

<div class="container">

<div class="row">

<div class="col-sm-3" style="background-color: lavender;">.col-sm-3</div>
 
<div class="col-sm-3" style="background-color: lavenderblush;">.col-sm-3</div>
 
<div class="col-sm-3" style="background-color: lavender;">.col-sm-3</div>
 
<div class="col-sm-3" style="background-color: lavenderblush;">.col-sm-3</div>

</div>

</div>