Spoilers do not show on either the grey or black themes

Summary

Both for me and another user (@Mecke#0000), spoilered text (IE what's between two sets of | characters) don't contrast well at all with the background. This is true with both the two darker pre-shipped themes and with several custom themes from the Fluxer Themes server.

Steps to reproduce

1. Apply a dark theme (in this case the Fluxer "Dark" or "Coal" ones)
2. Send a message surrounded by four |, two on each side.
3. Tada! No way to see it unless you've got the colour perception of a mantis shrimp.

Environment (optional)

Firefox, macOS X.

Logs or screenshots (optional)

My image: image Mecke's image: image