to get transparent (default) buttons. The difference is only in the color of the text.
You can combine
Wrap a series of buttons into groups.
Wrap a series of buttons with
Combine sets of
.btn-group into a
.btn-toolbar for more complex components.
Make a set of buttons appear vertically stacked rather than horizontally
Instead of applying button sizing classes to every button in a group, just add
.btn-group-* to each
.btn-group, including when nesting multiple groups.
.btn-group within another
.btn-group when you want
dropdown menus mixed with a series of buttons.