Historians do not use "Dark Age" for Greece. The term "Greek Dark Ages" (c. 1100–800 BCE) exists but refers specifically to the post-Mycenaean collapse—loss of Linear B writing, palatial centers, trade networks, and population decline—not a cultural void.
In European history, "Dark Ages" (c. 476–1000 CE) describes the early Middle Ages after Rome's fall—characterized by fragmented politics, reduced literacy, and limited surviving records (hence "dark" to historians).
So: Greece had a post-palatial transition, not a "Dark Age" in the medieval European sense.