margin auto bootstrap 3 code example
Example 1: centralize div bootstrap
<div class="row align-items-center justify-content-center">
<div class="col">This will be centered vertically and horizontally</div>
</div>
Example 2: columns center bootstrap 3
<div class="row">
<div class="col-md-2 col-md-offset-5"></div>
</div>