Ask for advice: what does "Zhongshan is immortal" mean, and the origin of this sentence?

Zhongshan is not dead, and the country seeks great harmony.

"Zhongshan will not die, and the country will seek great harmony" is the slogan of Peking University students when Lien Chan gave a speech at Peking University. Looking back on the cooperation between countries in the past, it is not difficult to find that Sun Yat-sen and the Three People's Principles are the bridge of political party reconciliation. Two political parties, one flag. Respect for Sun Yat-sen is a knowledge that transcends political views and positions. ...