Bootstrap 3: pull-right for col-lg only

Answer 1

There is no need to create your own class with media queries. Bootstrap 3 already has float ordering for media breakpoints under Column Ordering: http://getbootstrap.com/css/#grid-column-ordering

The syntax for the class is col-<#grid-size>-(push|pull)-<#cols> where <#grid-size> is xs, sm, md or lg and <#cols> is how far you want the column to move for that grid size. Push or pull is left or right of course.

I use it all the time so I know it works well.