Where does "Chang 'e should regret stealing the fairy medicine, blue sky and night heart" come from?

The mica screen was deeply shaded by candles, and the long river gradually sank.

Chang 'e should regret stealing the elixir, the sky is high and the clouds are light, and the night is clear and refreshing. It's the Goddess Chang'e flying to the moon by Li Shangyin. There are always different interpretations of this poem. Some people think it's a satire on a female Taoist priest, some people think it's a mourning, some people say it's a sign of being "detained", and some people say it's a confession. These statements are not subjective, and it is best to understand what is described in the poem. The title of the poem is Chang 'e, but it is not about the fairy Chang 'e on the moon. It seems to describe the feelings of a woman who is in a similar situation and mood to Chang 'e. The first sentence describes the situation indoors at night. There is a delicate mica screen in front of the bed. The night is already deep, the candlelight is dim, and the candlelight shadow on the screen is getting darker and darker. Here, the word "deep" is used to express the candle shadow, and it is also used to express the depth of the night, suggesting that the heroine is lonely and sleepless. The second sentence is about outdoor scenery. The heroine stayed up all night and looked up in court. It was dawn and the Milky Way had gradually moved westward. The morning star appears in the eastern sky, but as the sky is about to dawn, the morning star gradually disappears. The word "gradually" in this sentence shows that with the passage of time, the lonely heroine will spend another sleepless night. The characteristics of these two sentences are to render the atmosphere of the environment and set off the lonely feelings of the heroine. Write three or four sentences about the heroine to expand her imagination. She remembered the moon and the morning star from the Milky Way, the fairy in the moon from the moon, and the loneliness after the Goddess Chang'e flying to the moon. Combined with her single room, she naturally has the idea of regretting stealing medicine to the moon. Although this is a fictional word, it is reasonable. The whole poem expresses the feeling of loneliness and cold, and of course it also entrusts the poet with a sense of life experience.