Offset bootstrap 3
col-sm-offset-2
Worried Whale
col-sm-offset-2.col-6{
flex: 0 0 50%;
max-width: 50%;
}<div class="col-lg-2 col-md-4 col-sm-3 "> Your Stuffs </div>
/*
col-lg for large
col-md for med
col-sm for small
enjoy :)
*/
.col-12{
flex: 0 0 100%;
max-width: 100%;
}<div class="row">
<div class="col-sm-9">
Level 1: .col-sm-9
<div class="row">
<div class="col-8 col-sm-6">
Level 2: .col-8 .col-sm-6
</div>
<div class="col-4 col-sm-6">
Level 2: .col-4 .col-sm-6
</div>
</div>
</div>
</div>