As far as I understand, Anki uses default CSS.
But this:
.card {
font-family: sans-serif;
}
does not make card font to be sans-serif. Specifying something specific, like Arial, works fine.
Is it a bug?
If you do not have that font installed (or the name is not matching for some reason), it should not work.
This is a toolkit bug. Do you experience the same issue in the latest beta version, which uses a newer toolkit? https://betas.ankiweb.net/#/
I’m afraid, I do (2.1.28beta4-116aeead for macOS). See screenshot.
Side note: the new dialogue window is too wide, it doesn’t fit the screen.
Unfortunately the toolkit doesn’t support word wrap in the radio buttons (front/back/style, etc). Would it be possible to make those translations shorter? That will allow the dialog to be smaller.
The font issue looks like yet another toolkit bug that they don’t have immediate plans to fix 