What is the default display property of the :before and :after pseudo-elements?

Question

What is the default display: properties of :AFTER and :BEFORE pseudoelements after you specify content.

Is it display: inline

Answer 1

The :before and :after pseudo-elements are inline by default.

As the W3 spec says:

In a :before or :after pseudo-element declaration, non-inherited properties take their initial values.

And the initial value of the display property is inline.