@mixin responsive-font($min, $max, $screenwidth) {
  $max-unitless: $max / ($max - $max + 1);
  $responsive-unitless: ($max-unitless/$screenwidth)*100;
  $fallback: false;

  $responsive: $responsive-unitless+vw;
  $dimension: 'width';
  $min-breakpoint: $min / $responsive-unitless * 100;

  @media (max-#{$dimension}: #{$min-breakpoint}) {
    font-size: $min;
  }

  @if $max {
    $max-breakpoint: $max / $responsive-unitless * 100;

    @media (min-#{$dimension}: #{$max-breakpoint}) {
      font-size: $max;
    }
  }

  @if $fallback {
    font-size: $fallback;
  }

  font-size: $responsive;
}