gtk: is there a way of setting the `light/dark' style fields from a gtkrc file?

[Miles Bader <miles lsi nec co jp>]

[I use gtk on debian, so perhaps some of the following message is a bit
debian specific (I originally sent it to a debian mailing list).
However, I think the main question (at the end of the message) is not.]

I downloaded the debian `gtk-engines-icegradient' package, which is
cool, but I like a dark theme, so I copied the IceGradient theme and
changed the colors to be darker, e.g.:

  fg[NORMAL]       = "#E5E5E5"
  fg[ACTIVE]       = "#E5E5E5"
  bg[NORMAL]       = "#404040"
  bg[ACTIVE]       = "#505050"
  (etc)

This gives a dark general color to things, _however_, the 3d-ness
doesn't look very good, because the `highlight' color that gets used is
much too dark.  I looked at the source code for the icegradient engine,
and notice that it seems to get that highlight color from
`style->light_gc[state_type]', and if I try to do something like
`light[...] = ...' in my gtkrc file, it gives an error, so I guess this
field is automatically calculated.

My question: is there anyway to influence how gtk calculates the `light'
(and perhaps `dark') colors, so they look better with my dark color
scheme?  It seems like the method it uses only works well with bright
colors.

Thanks (and apologies if I'm totally off-base about how this stuff works),

-Miles

-- 
Come now, if we were really planning to harm you, would we be waiting here, 
 beside the path, in the very darkest part of the forest?