Using 'overflow' in 'flex-grow'
Situation
In general, to use 'overflow', the target should have a length.
However, even though the target doesn't have a length, if 'flex-grow' is used, 'overflow' can be applied.
However, the parent should have a length.
However, even though the parent doesn't have a length and 'flex-grow' is used, if the element itself has a length, 'overflow' can be applied.
Example 1: The Parent Has a Length