class's nth child code example
Example: css nth child
/* Select the first list item */
li:nth-child(1) { }
/* Select the 5th list item */
li:nth-child(5) { }
/* Select every other list item starting with first */
li:nth-child(odd) { }
/* Select every 3rd list item starting with first */
li:nth-child(3n) { }
/* Select every 3rd list item starting with 2nd */
li:nth-child(3n - 1) { }
/* Select every 3rd child item, as long as it has class "el" */
.el:nth-child(3) { }