Why do you think some historians describe the event ( Soviet invasion) in Afghanistan as the "Afghanistan Miracle"?

The Soviet invasion of Afghanistan took place between 1979 and 1989. It faced the Soviet Union (which supported the Marxist-Leninist government in Afghanistan) and the Afghan Islamic Mujahedin movement. The rebels were backed by the United States, which saw it as part of the Cold War. Already in 1978, an uprising against the Soviet-backed government that took power began. The uprising only worsened when the Soviet Union joined a large number of troops and occupied the country in December 1979. However, despite the notorious military and economic superiority of the Soviet forces and the Afghan government, the invasion lasted 10 years, and was finally defeated by the Mujahideen forces. The fact that the mujahideen fought inspired by religious convictions helped to defeat a Soviet army that was tired of fighting in a foreign conflict. However, the fact of the victory of the weakest side in this conflict was cataloged by historians as the Afghan Miracle.

b or c ( this is because my answer is short so just ignore it)