Pronunciation of 'vin'
I always (and so do all my English friends) pronounce 'vin' as van not von as in Duolingo. Is the Duolingo version perhaps a US, Canadian or regional pronunciation? Hearing it for the first time I assumed it was 'vent'. Which made 'vous avez le vin' sound quite amusing!
The thing is that it is a nasal vowel /ɛ̃/ which you don't have in English. As far as I can tell, it is pronounced at the same place as the <e> in "vent" but nasally.
As a follow-up, I just did the first food section, and I got both pronunciations of 'vin' - which is guaranteed to confuse
Part of the problem probably stems from the fact that in a lot of prominent dialects of French (Parisian in particular) the pronunciation of the nasal vowel in 'vin' /vɛ̃/ shifts and ends up pronounced as /vɑ̃/, which is coincidentally the same vowel in the word 'vent'.