CSS how to use pseudo-class :not with :nth-child

:not(:nth-child(4n)) will get you anything that isn't :nth-child(4n), i.e. anything that isn't the 4th, 8th and so on. It won't exclude the 2nd child because 2 isn't a multiple of 4.

To exclude the 2nd and 4th you need either one of:

• td:not(:nth-child(2n)) if you have fewer than 6 columns, or

• td:not(:nth-child(2)):not(:nth-child(4)) if you have at least 6 columns and only want to exclude the 2nd and 4th, and not every even column.

Demo