I compared them - and you're still not sanitising the $_POST inputs amongst some other bad practices. So it's great that you've made this and put a substantial number of hours into creating themes for it - but in it's current state (looking at all the branches in your github) it's not fit for purpose.

If you hosted this online, you're simply providing a platform for malicious users to gather targets or worse.

What was/is the goal of this project? To make the smallest CMS? To try your hand at making a CMS and to learn from it? This is unclear.