We say both доброй ночи (kind night) and спокойной ночи (calm night) as a wish to sleep well or as a farewell when it happens really late, so the meaning is the same. We never use спокойный день or спокойного дня in this meaning. You can say спокойный день just in a talk, it means that today everything goes calm, without troubles.
We really often use добрый день (kind day) / доброе утро (kind morning) / добрый вечер (kind evening) as a greeting.
We often say хорошего дня (good day) / хорошего вечера (good evening) as a farewell in formal way, for example after business meeting. And we don't say хорошего утра (good morning) in this meaning. If farewell happens in the morning, we also say хорошего дня (good day). In these expressions we imply "I wish you ..." but we don't say it. Please pay attention: хорошего дня - farewell, хороший день - NOT farewell, just saying that the day is good, for example the weather is fine and all goes well.
So it may be strange that similar expressions are used in a different situations. Overall: доброй/спокойной ночи - both farewell when it's late and wish to sleep well; добрый вечер/день and доброе утро - greeting in the evening/afternoon and in the morning; хорошего вечера - farewell at about 4-8 p.m.; хорошего дня - farewell in the morning and afternoon; хороший вечер/день and хорошее утро - neither farewell nor greeting, just talking about the weather or how it is going.
P.S. день and вечер are masculine, утро is neuter, so the ending of the adjectives хороший, добрый, etc. are different.
Yeah, it depends on the word it's describing. There are a few rules to help you remember - words ending in consonants are masculine, words ending in -а or -я are feminine, words ending in -о or -е are neuter. Words that end in -ь can be either masculine or feminine and those ones need to be memorised. The adjective endings are more or less the same - for this example, добрый is masculine, добрая is feminine, доброе is neuter. It's quite easy to get used to the patterns with practice and time :)
i'm new to russia and ye it's kinda it's depending on gender and word ending you can search to know which is masculine or feminine by searching on google russia word ending is a or ya so it's feminine and й for masculine е is for neuter and я is for feminine example from the basic i was finished мой папа моя мама моя пицца мой свитер
Russian doesn’t really have a word for ‘afternoon’. The most common ways to express the idea are «втора́я полови́на дня» ‘second half of the day’ or «[вре́мя] по́сле обе́да» ‘[time] after lunch’, but they don’t really work in the greetings.
Why is the ы necessary when there is already a й? Also, why does the word день need the ь?
I wish I could get an example of English letters that make the same sounds, but I guess those letters don't exist in the English language. That's why it's so hard to understand how to pronounce them in Russian. From the examples of pronunciation I have heard from Duolingo, е, й, and ы, and even и sound so similar, that I can't hear the difference. Same with ь. I can't hear the nuance of that character, and I don't know what in means to soften the n sound. An "n" is an "n" to me.
Yeah, the Duolingo pronunciations can make it tricky to get used to the sounds in any language. But if you spend a little time listening to native speakers you should pick up on it fairly quickly. This is an oversimplification but here's a guide for the vowel sounds:
й: the 'y' in 'key' (or in 'yeh' without the 'eh', always combined with other vowels)
ы: the 'u' in 'sugar' (sound is formed towards the back of the mouth)
Hard/soft sounds can be harder to distinguish but again it gets easier over time. And rest assured you will be understood by native speakers even if your pronunciation is a little off :)
Because Russian is not Polish? In Russian you say "доброе утро" in the morning; "добрый день" during the day and "добрый вечер" in the evening. There's no exact rule as to when "утро" ends and "день" begins, but I would say it's roughly about at 10 a.m. when people stop saying "доброе утро" and switch to "добрый день".