twitter-bootstrap-3 Grid System Column wrapping
Example
If more than 12 columns are placed within a single row, each group of extra columns will, as one unit, wrap onto a new line.
<div class="row">
<div class="col-xs-9">.col-xs-9</div>
<div class="col-xs-4">.col-xs-4<br>Since 9 + 4 = 13 > 12, this 4-column-wide div gets wrapped onto a new line as one contiguous unit.</div>
<div class="col-xs-6">.col-xs-6<br>Subsequent columns continue along the new line.</div>
</div>
