The code and concept is heavily inspired (and partly copied for the first few levels, with permission - thanks Greg) by Chrunchzilla's Code Monster.
Every step of every level has its own code, which you can modify. That code is stored per-page in the browser's storage so will persist across refreshes and enables you to go back and forward between pages without losing any code. Resetting the code on any page sets it back to its original state.
There's no signing in and your data isn't stored on a server, so no need to warn about cookies and no GDPR concerns. The only reason to enter your name is so I can see it on the screen if I'm teaching you in my classroom.
I loathe slow websites, which is why I coded this one to be super-speedy. All code for the whole tutorial loads on the first page, in well under 1 second. This is how the web should be. If you end up becoming a web developer yourself... please, please keep file sizes down and the speed high.
Happy coding! 😎