Style SharePoint 2010 lightboxes

The lightboxes in SharePoint 2010 is kind of nice. They allow you to open your pages in a modal (resizable) window. By default, the top navigation and quick launch will be hidden in the lightbox. This is done by adding the class s4-notdlg to the containing html element.

If you want some special style on an object when it is opened in a lightbox you use the class ms-dialog

Examples:
<span class="s4-notdlg">This will not show in lightboxes</span>

<style>
/* Makes the body background pink in a lightbox */
.ms-dialog body
{
background-color: pink;
}
</style>

PS.
Open a lightbox with the following JavaScript:
var options = {url: http://myspsite/default.aspx};
SP.UI.ModalDialog.showModalDialog(options);DS.