Use CSS media queries to set the most appropriate typeface, weight, and size for each kind of screen
David Demaree, writing for Typekit:
Because hi-DPI browser support is still fairly new, there isn’t yet a standard media query for detecting hi-DPI displays. However, all major browsers do support at least one syntax for detecting screen resolution, and you can combine the most common syntaxes to produce a “bulletproof” query for styling hi-DPI web content.
Don’t miss David’s Gist that shows how to set this up as a Sass mixin.