Help with Polish language - I'm confused by the noun change when a negation is added - genitive case

Hello (and I apologize if this has been covered, I'm new here). I'm learning Polish through Babbel for an upcoming trip to Poland. And I'm confused by the noun change when a negation is added. For example: I like beer: Lubie piwo - But I don't like beer: Nie lubie piwa. Why does "piwo" change to "piwa" with negation. I've noticed the same with wine. Your help is greatly appreciated.

in the Polish language nouns get declined - meaning they acquire new endings for different 'cases' and sometimes (less often) experience a change to the core of the word - which case is used in a sentence is typically governed by the verb or the position in the sentence - typically the active side (the subject of the sentence) is in the case known as 'nominative' - in Polish dictionaries words are listed by their nominatives - there are 6 other 'cases' - in this case the verb 'lubię' requires the accusative form/'case' - it happens so that the nominative and accusative of 'piwo' are the same - however the negation of verbs typically requires a different 'case', namely genitive - the genitive of 'piwo' is 'piwa' - in the singular 'piwo' may go under all these forms: piwo, piwa, piwu, piwie, piwem depending on the role in the sentence (whether it is a subject or object of the verb/sentence and depending on the verb in question - various verbs require different cases also various pronouns (in, above, under, around, on etc) require particular cases of the noun that they are attached to

long boring historical reasons.....

the upshot is that the accusative can't appear after a negative verb and it gets changed to genitive.. no other cases change like that, just the accusative after verbs think of it a little like English

Do you have some bread?

No, I don't have any bread. (why does 'some' change to 'any' in the negative?)

Thank you!! Yes, this makes much more sense. I hope I can grasp at least a little before I go there!

Right, maf!

@Suze, the genitive in Polish acts rather like adding "much"/"many", "how much/many of" in English. The difference is that Polish doesn't always make the same

distinction between singular and plural as in English, the reason why Poles often say or write, "We have much of forests in Poland.." or similar transference errors.