As updated on September 14, 2016 Gmail will support media queries. Though this hadn’t been enrolled at the point of writing it is expected to be done with next updates of the app.
List of Gmail supported CSS properties and media queries can be found here.
So what does this mean to the eDM designer and developer? Well, in short it means a lot. Previously, there were fair bit of workaround involved to make eDMs responsive in Gmail Apps. But with the support of the Gmail for media queries it does bring freedom for creativity for email designer and makes life easy for a web developer like myself.
This does lead to the fact that media queries support will be a standard.