A SASS mixin to easily add thin borders to your elements.
On a retina device using the classic
.foo
border: 1px solid black
will render 2 physical pixels. This mixin creates a fake border, with a svg line in the background of your element. The render of the line will be 1 physical pixel on a retina screen.
.foo
+retina-border(top $primary-color, bottom #bada55)