How to Customize the GIMP User Interface | GIMP for Beginners

To back the stage background black, I edited C:\Program Files\GIMP 2\share\gimp\2.0\themes\Dark\gtkrc.

  color["clrA"]  = "#303030"
  color["clrB"]  = "#000000"

  fg[NORMAL] = @clr2
  fg[PRELIGHT] = @clr2
  fg[ACTIVE] = @clr3
  fg[SELECTED] = @clr1
  fg[INSENSITIVE] = @clr3

  bg[NORMAL] = @clrB