Is the winter solstice a lunar or solar festival?

I think this festival is a mixture. First of all, the date of winter solstice is really related to the earth's revolution around the sun, which is the algorithm of solar calendar. The lunar calendar is based on the moon revolving around the earth. But the lunar calendar is not equal to the lunar calendar, which means that the lunar calendar is actually a mixture of the solar calendar and the lunar calendar. The solstice in winter is a festival in the lunar calendar. However, the 24 solar terms, including the winter solstice, adopt an algorithm similar to the solar calendar. The lunar calendar belongs to a kind of lunar calendar, and an average calendar month is equal to a new moon. However, the leap month is set to make the average calendar year a tropic year, and the 24 solar terms are set to reflect the changing characteristics of the seasons (the annual movement of the direct point of the sun), so there is also a solar calendar.