What do you mean, the autumn water is traceless, and the sunset snow in Qian Shan?

No trace of autumn water: the wind blows over the water and sets off a wave. After the wind passed, the water surface returned to calm, leaving no trace.

This is used to describe that although I was slightly disturbed by something, I was calm again and didn't care at all.

Sunset Snow in Qian Shan: At night, snow and ice cover endless peaks.