Alternating POST Colors?

[Dudeness]

How can I create alternating row post colors? For example post 1. has a gray row background and post 2. has a green background.

The avatars and such should stay on the left side. I found ways to do this for the home and threads list but not posts inside threads.

For example see this thread. (http://www.neogaf.com/forum/showthread.php?t=342018&page=512) It has alternating light and darker gray post colors.

Can anyone please tell how to do this?

[Dismounted]

You can edit the postbit/postbit_legacy template and use a conditional to decide on a colour (and insert the appropriate CSS/HTML).
<if condition="$post['postcount'] % 2">POST IS EVEN<else />POST IS ODD</if>

[Dudeness]

Okay well I'm not a savvy html coder though. Can I paste that in the postbit and what else needs to be added?