"Some media features with a 'range' type are said to be false in the negative range. This means that negative values are valid and must be parsed, and that querying whether the media feature is equal to, less than, or less or equal than any such negative value must evaluate to false. Querying whether the media feature is greater, or greater or equal, than a negative value evaluates to true if the relationship is true."

https://drafts.csswg.org/mediaqueries-5/#false-in-the-negative-range