@media [type] and [condition] … not [condition] { …}@media [condition] and/or/not [condition] … { …}其中：
type = "all" | "print" | "screen" | "speech"condition = equality | comparisonequality = name ":" valuecomparison = name ("<"|">")? "="? valuename = <CSS property name>value = <CSS property value>
