Can anyone explain this?

Question

:not()

This selector only applies to one element; you cannot use it to exclude all ancestors. For instance, body :not(table) a will still apply to links inside of a table, since <tr> will match with the :not() part of the selector.

Ref:https://developer.mozilla.org/en-US/docs/Web/CSS/:not#description

Answer 1

Maybe related somehow

https://www.sololearn.com/Discuss/2352863/?ref=app