AskRIWebmaster on "[Plugin: Contact Form 7] Alignment of the Checkboxes"

So I tried adding
span.wpcf7-list-item { display: block; }
to my css file and nothing changed for any of my forms.

Do I replace "wpcf7-list-item" with the id I gave the check boxes? Or can I add a class to the tag to specify the check boxes?

Thanks for your quick reply!