Is the zodiac calculated according to the lunar calendar or the solar calendar, and the dividing line is New Year's Day or Spring Festival?

Zodiac is unique to the lunar calendar in China, so it should be counted according to the lunar calendar.

The dividing line of the Lunar New Year is beginning of spring, not Spring Festival, not New Year's Day. ?

Note: 1. New Year's Day is the dividing line of the Gregorian calendar.

2. Spring Festival is the most important traditional festival in China, but it is not the "Spring Festival" in climate. Climate "Spring Festival" refers to the beginning of spring. ?

3. beginning of spring: The weather began to improve and everything began to recover.