What is the ruling on browsing horoscopes for entertainment while being ignorant that it is a form of shirk, and is this considered among the types of shirk that are unforgivable?

Reading horoscope pages is forbidden by Islamic law. It is not major shirk that expels one from the faith. You may not be sinful for what happened in the past due to your ignorance of the ruling. However, you must avoid it now. The shirk that Allah does not forgive is that from which its perpetrator does not repent. As for sincere repentance, it is accepted even from major shirk, for Allah replaces the bad deeds of those who repent with good deeds and forgives all sins.