What are the differences between Li Qingzhao's poems in the early and late periods?

The language of Li Qingzhao's early ci is fresh and natural, cheerful and cheerful, occasionally dotted with leisure worries, such as the fine print "like a dream"

However, the tone of the late ci is mainly sad, and the sadness is much heavier than that in the early period, such as "cold fragrance and new dreams are gone, and people can't afford to worry", "I am happy all night, dreaming of Chang 'an Road", "boating on two streams, I am afraid I can't afford many worries" and "I am haggard now.