This is something that we're working on integrating into
TileMill - here's the issue in
the codebase tracking the feature. For the time being, I'd
recommend having a separate stylesheet or a part of your stylesheet
that you can comment-out (if you need normal web output as well)
with larger type and styles tweaked for Retina-display devices.
Support Staff4 Posted by AJ on 21 Feb, 2012 03:56 PM
I don't think we have an example, but you'll probably want to
start by increasing all your zoom level filters by one and doubling
all of your line-width, marker-width, and text-size dimensions and
see how that looks.