Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.4.12)
// Compass (v1.0.3)
// ----

/*
* FlowType Sass Mixin 1.1
*/

// Establish default settings/variables
// ====================================
$minimum: 500;
$maximum: 1200;
$minFont: 12;
$maxFont: 40;
$fontRatio: 30;

// Mixin start
// ===========
@mixin flowtype($maximum, $minimum, $maxFont, $minFont, $fontRatio) {
  $fontSize: $maxFont;
  $tempFontSize: $fontSize;

// Output media query for minimum size
// ===================================
  @media screen and (max-width: #{$minimum}px) {
    font-size: #{$minFont}px;
  }

// Do the magic math
// =================
  @for $i from $minimum through $maximum {
    $fontBase: floor($i / $fontRatio);
      
    @if $fontBase > $maxFont {
      $fontSize: $maxFont;  
    }
    @else if $fontBase < $minFont {
      $fontSize: $minFont;
    }
    @else {
      $fontSize: $fontBase;
    }

// Output media queries
// ====================      
    @if $tempFontSize != $fontSize {
      @media screen and (min-width: #{$i}px) {
        font-size: #{$fontSize}px;
      }
    }

    $tempFontSize: $fontSize;
  }
}

body {
  @include flowtype($minimum, $maximum, $minFont, $maxFont, $fontRatio);
}

SassMeister-output.css

/*
* FlowType Sass Mixin 1.1
*/
@media screen and (max-width: 1200px) {
  body {
    font-size: 40px;
  }
}