About CSS3:nth-child() selector_html/css_WEB-ITnose

A page with many small squares. The class of the big square is big and the class of the small square is small. Use the css3 selector to write this:

.small:nth-child(even){margin-right:0;}

Set the even-numbered small The margin-right of the square is 0, but the margin-right of the third small square is equal to 0. What's going on?

demo: http://guusoft.com/test/

Reply to discussion (solution)

Through the guidance of other netizens , understand that selecting the odd-numbered or even-numbered child element from the parent element does not specify a certain type (.small), but all child elements are counted.
So the final solution is:

$(".small:odd").addClass("last");