Cellpadding and cellspacing not working in Firefox and Opera

Except the Garland theme does add cellpadding and cellspacing. Seems like a CSS issue but not sure where all other themes are getting the style from, must be padding:0; some where. Have commented out all style relating to tables, seems to get the style from the div. Even if I set style.css to use

td { padding:4px;}

No difference. That's using theme's style.css. Any ideas much appreciated.