Webcomponents Vaadin Grid reorder cell background

When reordering the columns in the Vaadin grid the background changes to black, as defined in the CSS from “vaadin-grid-column-reordering-behavior”. I would like to change the background color, but except doing it directly in the Bower component I cannot change the background…

:host([reordering]
) .vaadin-grid-cell {
background: #000;
}
:host([reordering]
) .vaadin-grid-cell[reorder-status=“dragging”]
{
background: var(–primary-color, #000);
}