Q:

css nth-child and classes

I've got a problem with the css nth-child selector.
I have a grid of 3x3 elemtens inside a container. Those elements have a class called .square.
With .square:nth-child(3n+1) I select every first element of the row and color it green.
With .square:nth-child(3n+3) I select every last element of the row and color it red.
This works fine, until there is any element(<br> for example) that is outputted before the grid. With every new <br>, the order moves up by one, as is the <br> was considered a .square.
As I understand the .nth-child, it should select every third element of the .square class. Why does it apply that to any element, and how can I achieve my inital goal?
Thanks in advance
http://www.hier-krieg-ich-alles.de/shop.php?cat=26491127728
The problem occurs on the boxes in the middle.

A:

Sounds like you want nth-of-type.
Related selectors which you may find useful are :first-of-type, :last-of-type, :nth-last-of-type and :only-of-type.

