SVG strokes in 'currentColor' from (https://cdn.rawgit.com/blampe/goat/master/examples/trees.svg) et al. render as black, irrespective of page background color. If the user happens to have set one of the Github "Dark ..." per-user Theme, result is black strokes on a background in some shade of dark-grey, possibly indistinguishable on certain monitors.
SVG strokes in 'currentColor' from (https://cdn.rawgit.com/blampe/goat/master/examples/trees.svg) et al. render as black, irrespective of page background color. If the user happens to have set one of the Github "Dark ..." per-user Theme, result is black strokes on a background in some shade of dark-grey, possibly indistinguishable on certain monitors.
Theme setting: (https://github.com/settings/appearance)
Verified on Firefox and Safari.