Is there any sort of easy way or helper that would enable to functionality to set custom variable flags. For example I could set a color variable to "blue" in the editor and I could use handlebars to add the "blue" class an element in that post.
EDIT: I ended up having to use a different CMS. Ghost was made intentionally to be simple and my needs require more customization features.
This is something I have been trying to figure out, but (being new to ghost), I haven't found a clean way to do this. Unlike Wordpress, there is no field for this in the editor (I have checked the documentation, nothing similar), so you have to apply some custom solution. Here are two options:
If the styling you want to apply depends on a tag, e.g. if 'movie'-tagged posts need some special styling, you can just add CSS because the {{body_class}} helper adds all the tags to the <body> element as tag-classname, e.g. tag-movie.
If tags are not your option, you could use client side JavaScript, check some condition in the content and apply the styling. I use this to change color of an svg logo when it is placed on a hero image that happens to have the same color as the logo. This requires the hero image of the post to follow some url convention, like post-heroimg3663-blue.jpg. Then you can add some inline Javascript to the <head> to change the color of the logo. Not so good, but it should work.
UPDATE:
If the second option works for you, you could even consider creating a Handlebars custom helper and running any styling (via adding a class) on the server side.