There is a solution, however. Benjamin Drung (bdrung) wrote
Ambiance," and change the default colour to black. To fix the problem:
- Open the gtk theme for Ambiance
themes/ Ambiance/ gtk-2.0/ gtkrc)
- Search for ntext_color
- Replace #3C3C3C with #000000
Re-load LibreOffice; problem solved.
Why LibreOffice uses the GTK theme system to determine its "Automatic" colour is beyond me; this seems like a very irritating "feature."