Unique page/post background images by array, table or stylesheet

when asking:
“i’ve been told it’s “impossible” to set a unique background for each page/post (in wordpress)… i refuse to acept that. how can it be done?”

i was given the following answers…

“not impossible at all. just create an array of post_id’s => background_colors or set up a new table in the wp database.”

“you could include a completely separate stylesheet for every post if you really wanted to”

” #post-1234 {background:etc} #post-1235 {background:etc} “

i am still new to wordpress, css and so on, so that doesnt immediately make the solution apparent.

how does one apply this?

the where and how.

i’ve been looking through several dozen how-tos, and tutorials and wikis etc… with prompt progress looking scarce. anyone know any learning resource or something more likely to be relevant?

any help is massively appreciated. (been stuck for months looking how to do this, coulda done it in a second in plain ol html).