Alphabetical list of CSS at-rule descriptors.
About CSS At-Rule Descriptors
Some CSS at-rules accept values in the form of descriptors.
A descriptor is a declaration, of which has a name, a value consisting of a list of component values, and an
!important flag which is initially unset.
CSS descriptors typically look similar to CSS properties but the two are not to be confused. A descriptor is used within an at-rule for the purposes of setting a declaration within that at-rule. Properties typically appear in qualified rules, while descriptors appear in at-rules.