Help! Why is there 3 1 day between two solar terms in the online calendar? Shouldn't it be 30 days?

The number of days between two solar terms (i.e., non-neutral), such as 20 13 long summer (May 5 16: 18: 10) to Miscanthus (June 5, 20:23:20), the number of days is 3/kloc-. Therefore, it is normal that the interval between two solar terms is 3 1 day. In the lunar calendar, there is no neutral month, and the name of the month is the same as that of the previous month ... There are many rules and it is very complicated.