What is happening why is box not rotate

Question

https://code.sololearn.com/WhcWrLgoEEJo/?ref=app

Answer 1

css() jquery method change inlined style of elements selection... but you cannot set css variable through them ^^

however, this should work:
$(".div").css("transform", 'rotate(50deg)')

you could handle css variable values through dynamic stylesheets, but that's seems oversized for your target ;)

Answer 2

--rotation: 0;
.do changes in rotation instead of 0