Questions & Answers about Jag älskar litteratur, men jag läser den sällan nu.
Why is there no article before litteratur?
Because litteratur (literature) is an uncountable mass noun being used in a general statement. Just like in English, when you talk about a general uncountable concept, you do not use an article.
Why do we use den to mean "it" here instead of det?
The pronoun den refers back to litteratur. Because litteratur is an en-word, we must use the matching en-word pronoun den to say "it". If the noun had been an ett-word, we would have used det.
Why does the adverb sällan come after the object den?
Normally, a sentence adverb like sällan (rarely) comes right after the verb in a main clause. But there is a special rule in Swedish: if the object is a short, unstressed pronoun like den, it jumps ahead of the adverb. So we say läser den sällan rather than läser sällan den.
Does the word men affect the word order in the second half of the sentence?
No. The word men (but) simply links two independent main clauses without changing their word order. The second clause acts just like a normal sentence, starting with the subject jag followed by the verb läser.