Quick answer to a query we got asked the other day.
Does the css property z-index have a maximum value?

The answer is yes.
The maximum value for z-index is 2147483647.
The minimum value for z-index is 0.
Occasionally you may see a negative z-index e.g. z-index:-1, this is not supported by all web browsers however.

It’s also worth noting that z-index only applies to elements which are positioned using position: relative or position: absolute.