Interpretation of "wàn jiā dēng huǒ": Every family lights up to describe the prosperity of the city at night. From Don Bai Juyi's Wangjiang Nighttalk

Dēng huǒ lán shān is an idiom from Xin Qiji's Jade Case Yuan Xi in the Southern Song Dynasty.

1. Light and sparse, refers to a place with a vast land and a sparse population, which is relatively deserted.

In ancient times, after nightfall, every household held high the lights and didn't put them out until bedtime. Therefore, dim lights also represent "late at night" and when no one is around.

Every household is dimly lit. The original sentence "Where the lights are dim, there are several degrees of spring flowers and autumn moon"

Interpretation: The lights of thousands of families were gorgeous, but now they feel lonely and scattered. Beautiful scenery such as spring flowers and autumn moon should be appreciated, but it is just a passing sight because of sadness.