How do you separate jekyll site content and code into separate branches?

Hi I am using jekyll hosted on github oages and I would like to separate the content and code of my site into separate branches so:

1. It is more organised.
2. If I want to change some code in the site experimentally I can create A new branch based of the code branch and I don't have to worry about updating its contents when I create new blogs in my main code branch. I have done some research someone mentioned using gem files to store the code but creating a jekyll theme and distributing it with ruby gem seems a daunting task since I don't even know the gem programming language.

Any thoughts? And thanks in advance.