node ID on body tag?

I need to add a lot of styling individually on a lot of pages, so I was trying to figure out what to add to PAGE_CONTAINER so that it would get an #id which is the id of the node that it's displaying (should work for any type of content, be it a page, forum category etc. as their ID's should be unique)

Anyone who can point me in the right direction?
Have you modified either of these templates?

Admin CP -> Appearance -> Templates
> pagenode_container

Or have you possibly replaced them?

The body classes are defined in pagenode_container. Then they are rendered in PAGE_CONTAINER.
The PAGE_CONTAINER template has been edited, but the code for the <body> tag is identical to the one from the default style:
<body{xen:if {$bodyClasses}, ' class="{$bodyClasses}"'}>
The pagenode_container has not been changed and is identical with default.
Really weird, since it's a completely new install from just a few days ago, I can pastebin the PAGE_CONTAINER and pagenode_container templates if you want, but I don't see anything in them that should prevent the classes being added (it literally adds none of the classes to the body tag)