Style a multi-level menu in Wordpress
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<p>Hi i have a multi-level menu(with nested sub-menu) returned fom this php function:</p>

wp_nav_menu( array('menu' => 'Category' ));

<p>I'd like to add a "first-level" class to each of first level and a "second-level"  to each of seconnd level...and so on...</p>

<span>any help?</span>
