To change the background and font color for top menu on hover, submenu items, and current page items, add the following to your Appearance → Custom Design → CSS page:
#access ul ul {
background: #fff;
-moz-box-shadow: 0 3px 3px rgba(255,255,255,0.2);
-webkit-box-shadow: 0 3px 3px rgba(255,255,255,0.2);
box-shadow: 0 3px 3px rgba(255,255,255,0.2);
}
#access ul ul a {
border: 1px solid #ccc;
color: #222;
}
#access li.current_page_item ul a,
#access li.current-menu-item ul a,
#access ul ul li.current_page_item a,
#access ul ul li.current-menu-item a {
background: transparent;
color: #222;
}
#page #access li:hover > a {
background: #eee;
color: #000;
}
You can adjust any of the color codes in the example to your liking.