Changing the layout of the ipython widgets toggle buttons

These are the buttons that I'm trying to customize:

The code itself.

This is the result I want to get (edited by GIMP):

I want to keep these buttons stacked vertically (as shown in the edited image I made), but since I don't know much about CSS, I don't know how to do that. Any suggestion?

Solution

As Bananach said, layout=widgets.Layout(width='100px') will do it.

widgets.ToggleButtons(
    options=['A','B', 'C'],
    disabled=False,
    button_style='info', # 'success', 'info', 'warning', 'danger' or ''
    layout=widgets.Layout(width='100px')
    #     icons=['check'] * 3
)