Poetry from sunset to darkness

Sunset to dark?

Isn't it dark at sunset? It doesn't seem to take long.

Bai Letian's Ode to the Twilight River;

A sunset gradually sank into the river, half green and half green.

The loveliest thing is the ninth day of September. The bright pearl's bright crescent moon is shaped like a bow.

This is from sunset to full moon, that is, from sunset to dark.