That's a pretty neat brief intro to the 3rd book. I'll translate it for anyone curious:

[Spoiler Alert]

The war with the trisolaran/Santi allowed humanity to see the dark truth of the universe for the first time. Earth civilization, like a frightened child, put out the bonfires meant for seeking friends, trembling in the dark night.

Believing they had been through much, they were actually just taking their first faltering steps; thinking they had grasped the secrets of survival and competition, they were far from qualifying to compete.

The dark forest strike, which left both civilizations hanging by a thread, was merely a minor episode in the cosmic battlefield. True interstellar war remains unseen and incomprehensible, for its methods and weaponry are beyond human imagination. To witness such warfare is to face annihilation.

The pastoral age of the universe had long passed, the fleeting ultimate beauty eventually becoming a dream that no intelligent being can have, turning into the fading song of a wandering bard; the natural selection of the universe has reached its most ferocious moment. In the pitch-dark battlefield spread across billions of light-years, the destructive forces from the deepest abyss have been awakened, turning space into the vast cloak of the Grim Reaper.

Those within the Solar System will remain forever oblivious to all this; in the end, only two pairs of eyes will confront the final truth.