Grid Layout
.col
.col
.col
.col
.col
.col-3
.col-auto - variable width content
.col-3
.col-6
.col-6
.col-6 .col-sm-4
.col-6 .col-sm-4
.col-sm-4
.col-sm-6 .col-sm-order-2 .col-sm-offset-2
.col-sm-12 .col-md-6 .col-md-offset-3
.col-sm .col-sm-offset-1
.col-sm .col-sm-offset-1