Cssnth-child: select the 3rd column td in tr

Today, when I revised my company website, I encountered a css problem. The specific requirement is to set the border-right of the third column of td in the table to 1px. At first, we set a css class name for the td of the third column, then add css to the class name. After searching online, you can directly use the pseudo class nth-child of css without setting the class name. The specific css code is as follows.

Tr td: nth-child (3) {border-right: 1px solid # e5e5e5 ;}

Note: here the index is counted from 1.