"The night is purple."
Translation:La nokto estas violkolora.
I tried 'purpura' out of curiosity (and also not feeling like hitting my shortcut to switch to Esperanto keyboard this time) and it worked. :)
I still have great problems woth endings when is it a or o or n... like why is it Nokton and when it is not... is there any rule one could get explained?
Nokto means it is the subject of the sentence, while nokton means it is the object. In this case, the sentence is describing the night as a subject, so it is nokto.
"Nokton" is only used when "night" is the driect object of a sentence. In this case, there is no direct object. A direct object would be like "ŝi legas libron". Its happening to a book, not just describing how the book is. "Nokton" would be for something like "a scream pierced the night", which i don't know how to say in Esperanto.