Before you can enter, there are some things to know
The playground is meant to be a public coding dump in which no changes have been made whatsoever. It's still the old color palette, which is just a gray background.
Code is from across the Internet, so expect some things to work and some not. The code is provided as is and I will not be liable (if you manage to) damage your device(s), although I doubt the code in the Playground will do any harm.
To enter, there's a password which can be easily found through the source code of this page. Find it and enter it below. The Playground will probably stay as is for now.
Pick a Theme, any Theme. The choice is yours