Form margins : how to get rid of them

In ruby on rails i try to force the from_tag to have a margin of 0 but it doesn't seem to work. Forms always seem to have a margin inside a table.

<td><% form_remote_tag :url => {:controller => "sgpanel", :action => "remove_from_cart", :id => product.id,:ad => product.sguser_id, :class => "formnomargin"} do %> <%= submit_tag "Remove item" , :class => "medium" %>

input.formnomargin { padding:0; vertical-align: bottom; margin:0; }

input.medium { font-size:12px; width:85px; padding:0; vertical-align: bottom; margin-bottom:0; }

the default display mode of a form emlement is block, put it inline form{display:inline}