Source code columns
<div class="row"> <div class="col-sm-3">.col-md-3</div> <div class="col-sm-6">.col-md-6</div> <div class="col-sm-3">.col-md-3</div> </div>
SVG background
<div class="row"> <div class="col-sm-3">.col-md-3</div> <div class="col-sm-6">.col-md-6</div> <div class="col-sm-3">.col-md-3</div> </div>