Comparison of Du Fu's Poetic Styles in His Early and Late Periods

The most concise answer:

In the early days, I was in high spirits, such as "Looking at Yue from afar" and "Looking at the top of the mountain, you can see the other mountains all appear dwarfs under the sky."

In the mid-term, the country cares about its family and hates it, such as three officials and three parting, such as spring hope. Although the country is broken, the mountains and rivers will last forever, and the vegetation will spring back.

In the later period, he lamented hardships, as dignified as climbing a mountain, and Wan Li was sad about autumn. The guest lived with me for a hundred years, and I climbed this high alone.

There are also some lightly written poems, such as "Huang Si's maiden is full of flowers" and "Coming back from this mountain and crossing another mountain", but they are all on a whim, not mainstream, and are not included in the comparison of poetic styles.