Font-Size per Viewport

mixin.fontsize.scss

@mixin font-size($fs-map) {
  @each $val in $fs-map {
    $fs-breakpoint: nth($val, 1);
    $fs-font-size: nth($val, 2);
    $fs-font-color: nth($val, 3);
    
    @if $fs-breakpoint == null {
      font-size: $fs-font-size;
      @include font-color($fs-font-color);
    }
    @else {
      @media screen and (min-width: $fs-breakpoint) {
        font-size: $fs-font-size;
        @include font-color($fs-font-color);
      }
    }
  }
}

@mixin font-color($fs-font-color) {
  @if $fs-font-color {
    color: $fs-font-color;
  }
}