difference between Safari web inspector strike throughs

Question

In the below picture, the -webkit-box-shadow rule is crossed out in red while the -moz-box-shadow rule is crossed out in black.

What does each mean? (E.g. what is the difference between red and black strike through?)

Answer 1

A red strike through indicates an error, such as an invalid value or a syntax error, and a black strike through means that the rule is ignored, usually because it has been overridden.

In your example, the -webkit-box-shadow rule is crossed out in red because of an invalid value (rbga instead of rgba).