Stacking and z-index in CSS
A friendly reminder to don't change the z-index like gambling with the highest value, if it doesn't work as expected check the stacking context of the early elements in the hierarchy.
position is just one of the attrs creating stacking contexts. e.g. check isolation.
This is basic stuff for a lot of developers but is often misused anyway. Yes, read this whole thing first or continue gambling. 😉