Attempted to improve the output frame indicator border again. Using two
greenish colors: one dark surrounded by two ligther greens. Green is,
here, to symbolize something new (of course likely heavily
culture-dependent) with the combination of two different brightnesses
looking like double-lines and hopefully indicating "result" (equally
culture-dependent?).

Signed-off-by: Jakob Brandsborg Ehmsen <jakobehmsen.github@gmail.com>