The W3C specifications define the valid media features. Only the official and browser-specific media features should be used to get the expected impact in the final rendering.
== Noncompliant Code Example
----
@media screen and (unknown: 1000px) { .. }
== Compliant Solution
@media screen and (width: 1000px) { .. }
== See
* https://www.w3schools.com/cssref/css3_pr_mediaquery.asp[CSS Specification] - ``++@media++`` rule
