[DragonByte Tech]

That is the only thing I can think of, unless the custom style is using something different, you could do a search in templates for this:

.navtabs li.selected .popupbody li

Once you see which templates have that, open them up and then click on find and look for some code that looks like this:

.navtabs li.selected .popupbody li a {
    text-indent: 0;
    color: {vb:stylevar navbar_popupmenu_link_color};
    background: {vb:stylevar navbar_popupmenu_link_background};
    padding:{vb:stylevar popup_padding.paddingTop}{vb:stylevar popup_padding.units} {vb:stylevar padding};
}

Where it says, color: {vb:stylevar navbar_popupmenu_link_color}; that is the stylevar it is using.

Chris