Retina font-weight for thin fonts in HiDPI typography

example.less

@import "retina.less";

.body-text {
  .retina-font-weight();
}

retina.less

.retina-font-weight(@ratio: 1.25) {
    @dpi : @ratio * 96;
    font-weight: normal;
    @media only screen and (-webkit-min-device-pixel-ratio: @ratio),
           only screen and (min-device-pixel-ratio: @ratio),
           only screen and (min-resolution: ~'@{dpi}dpi') {
        font-weight: 300;
    }
}