Respond-to Mixin with .ie8 fallback

_respond-to.scss

@mixin respond-to($primary, $secondary:min-width) {
  @if $secondary == max-width {
    @media screen and (max-width: $primary - .001) { @content; }
  }
  @else if $secondary == min-width {
    @media screen and (min-width: $primary) { @content; }
    @if $primary == $large {
      .ie8 &{
        @content;
      }
    }
     @if $primary == $medium {
      .ie8 &{
        @content;
      }
    }
  }
  @else {
    @media screen and (min-width: $primary) and (max-width: $secondary - .001) { @content; }
  }
}