Gtk.Settings:gtk-color-scheme
"gtk-color-scheme" String : Read / Write
A palette of named colors for use in themes. The format of the string is <programlisting> name1: color1 name2: color2 ... </programlisting> Color names must be acceptable as identifiers in the <link linkend="gtk-Resource-Files">gtkrc</link> syntax, and color specifications must be in the format accepted by Gdk.color_parse.
Note that due to the way the color tables from different sources are merged, color specifications will be converted to hexadecimal form when getting this property.
Starting with GTK+ 2.12, the entries can alternatively be separated by ';' instead of newlines: <programlisting> name1: color1; name2: color2; ... </programlisting>
Since 2.10