Z-index mini framework for Coursemology

[ekowidianto]

There is no convention in using z-index in our codebase. To research and implement a mini framework for z-index usage. It's possible to extend tailwind utilities as well for this case.

ref: https://www.smashingmagazine.com/2021/02/css-z-index-large-projects/

[enkr1]

I'd like to take a look at this. Will audit the current z-index usage and propose a Tailwind-based framework.