bosstrap small medium large size

Grid behavior	Horizontal at all times	Collapsed to start, horizontal above breakpoints
Container width	None (auto)	750px	970px	1170px
Class prefix	.col-xs-	.col-sm-	.col-md-	.col-lg-
# of columns	12
Column width	Auto	~62px	~81px	~97px
Gutter width	30px (15px on each side of a column)
Nestable	Yes
Offsets	Yes
Column ordering	Yes