Can't change the css properties of jQuery UI dialog titlebar

Can't change the css properties of jQuery UI dialog titlebar

I can't change the background color of jQuery UI dialog titlebar. I am
coding like this:
jQuery("#divId").dialog({
title: 'Information'
});
jQuery("#divId.ui-dialog-titlebar").css("background-color", "red");
By the way, my application will open only in IE. I tried to detect
titlebar and footer css properties with IE developer tools, but it won't
detect titlebar and footer. But it recognizes css properties of
ui-dialog-content. Please suggest me.