For example, for @media screen, print "screen" should be black, and print should be gray. Unless the page is in the print mode, than it's vice versa. Graying out non-matching media query selectors is useful for unintuitive CSS queries: @media (max-width:9999px), (max-height:10px) and (max-width:10px) "(max-width:9999px)" should be black, as this query matches any page with the width < 9999px. "(max-height:10px) and (max-width:10px)" should be gray, as this query matches any page with the width and height < 10px.