'Darkness' in the Bible

I concluded that wisdom is more useful than foolishness, just as light is more useful than darkness.

The wise use their eyes, but the fool walks in darkness. I also perceived that the same outcome affects them all.

Furthermore, all his days he lives in darkness with great sorrow, anger, and affliction.

because stillborn children arrive in pointlessness, leave in darkness, and their names are covered in darkness.

Even if a person lives many years, let him enjoy them all, recalling that there will be many days of darkness to come all of which are pointless.