Screenshot of LibreOffice Writer 25.2 with the "dark" theme active. The interface is still light and no different from the default light theme, only the page background is black. The "automatic" font colour is also still black, as in the light theme.
https://static.mstdn.fr/static/media_attachments/files/114/109/537/286/883/140/original/d6cba292e47796c3.png