gtk3 css GtkTreeView column header color

[john beritz <jberitz gmail com>]

I'm using Gtk+-3.2.3 on Ubuntu natty. How can I set the column header color
for a list in a GtkTreeView with css? ( Header is visible )
I can set row color with:

GtkTreeView row  {
background-color: red;
}

So I tried this for the column header which doesn't work:

GtkTreeView column-header  {
background-color: red;
}