Howto set Styles select background-color (ComboBox)

Hi,

We have a problem with our CKEditor, in the combo box "Styles", normal, Title 1, 2, ... have the correct CSS for font-size, color, font-family, but not for background color !

So in some of our websites with white text and dark background-color, we cannot see content of the dropdown "Styles" menu (white texte on white background) !!

My question is how to set dynamically the background color of Styles dropdown menu or how to set '.cke_panel_frame' with CK api ?

We tried a lot of things, for example...
1. jQuery('.cke_panel_frame').css('background-color':jQuery('body').css('background-color'));
2. CKEDITOR.config.ckePanelFrameColor = 'rgb(255,0,0)';
But nothing's working !

Manually in CSS file, this code is working :
.cke_panel_frame {
background: #3e3d40;
}

but we are looking for a dynamic solution, because on some websites background-color changes on every pages.

Please help
Regards