Ask for the name of a romance novel

It was an old romance novel, probably from Qiong Yao's era. The female protagonist started to live with her mother, who had some mental problems. Later, she came to a new family. The male protagonist was an uncle, and there was a frail elder sister (or younger sister?) who was talented in painting. In the beginning, the male protagonist was his sister's tutor. Later, he also tutored the female protagonist. I still remember that the female protagonist's trigonography was not good. The female protagonist also had an affair with the uncle's son. The uncle had a garden in his house. There was an actor in the garden. Every night, he would sing,"Flowers are not flowers, fog is not fog, and dawn comes in the middle of the night." I still remember that there was a scene in which the male protagonist and the female protagonist kissed. On their chest was a blue flower given by their sister. The male protagonist also said that the female protagonist's eyes were amber. That's about it. I can't thank you enough.

Answer 1

This novel was called Imperial Capital.