Adding an ID of the specific page to a page type is a handy way to provide minor, page-specific, modifications, without creating a new page type for that purpose.

<div id="<?php echo $c->getCollectionHandle() ?>"> 
    <div id="main_body">

$c->getCollectionHandle() returns the handle of the page, properly formatted (that is, with spaces converted to dashes) to be used as an ID value.

Styles then can be added to target that ID or styles/IDs nested below.