In fact, CSS allows not only allow even/odd alternations, but arbitrary intervals. The keywords 'even' and 'odd' are just convenient shorthands. For example, for a long list you could do this: li:nth-child(5n+3) {font-weight: bold} This says that every 5th list item is bold, starting with the 3rd one. In other words, the items numbered 3, 8, 13, 18, 23, etc., will be bold. Even and odd columns The