spec/libsass/bourbon.hrx

<===> input.scss
@import "lib/_bourbon.scss";

box:hover {
  @include animation-name(scale, slide);
  @include animation-duration(2s);
  @include animation-timing-function(ease);
  @include animation-iteration-count(infinite);

  // Animation shorthand works the same as the CSS3 animation shorthand
  @include animation(scale 1s ease-in, slide 2s ease);
}

div {
  @include appearance(none);

   /* boo boo boo */
  // Multiple image assets
  @include background-image(url("/images/a.png"), url("images/b.png"));

  // Image asset with a linear-gradient
  @include background-image(url("/images/a.png"), linear-gradient(white 0, yellow 50%, transparent 50%));

  // Multiple linear-gradients - Demo
  @include background-image(linear-gradient(hsla(0, 100%, 100%, 0.25) 0%, hsla(0, 100%, 100%, 0.08) 50%, transparent 50%),
                             linear-gradient(#4e7ba3, darken(#4e7ba4, 10%)));

  // NOT SUPPORTED - Multiple image assets with shorthand notation
  @include background-image(url("/images/a.png") center no-repeat, url("images/b.png") left repeat);
}

<===> lib/_bourbon-deprecated-upcoming.scss
//************************************************************************//
// These mixins/functions are deprecated
// They will be removed in the next MAJOR version release
//************************************************************************//
@mixin box-shadow ($shadows...) {
  @include prefixer(box-shadow, $shadows, spec);
  @warn "box-shadow is deprecated and will be removed in the next major version release";
}

@mixin background-size ($lengths...) {
  @include prefixer(background-size, $lengths, spec);
  @warn "background-size is deprecated and will be removed in the next major version release";
}

<===> lib/_bourbon.scss
// Custom Helpers
@import "helpers/deprecated-webkit-gradient";
@import "helpers/gradient-positions-parser";
@import "helpers/linear-positions-parser";
@import "helpers/radial-arg-parser";
@import "helpers/radial-positions-parser";
@import "helpers/render-gradients";
@import "helpers/shape-size-stripper";

// Custom Functions
@import "functions/compact";
@import "functions/flex-grid";
@import "functions/grid-width";
@import "functions/linear-gradient";
@import "functions/modular-scale";
@import "functions/px-to-em";
@import "functions/radial-gradient";
@import "functions/tint-shade";
@import "functions/transition-property-name";

// CSS3 Mixins
@import "css3/animation";
@import "css3/appearance";
@import "css3/backface-visibility";
@import "css3/background";
@import "css3/background-image";
@import "css3/border-image";
@import "css3/border-radius";
@import "css3/box-sizing";
@import "css3/columns";
@import "css3/flex-box";
@import "css3/font-face";
@import "css3/hidpi-media-query";
@import "css3/image-rendering";
@import "css3/inline-block";
@import "css3/keyframes";
@import "css3/linear-gradient";
@import "css3/perspective";
@import "css3/radial-gradient";
@import "css3/transform";
@import "css3/transition";
@import "css3/user-select";
@import "css3/placeholder";

// Addons & other mixins
@import "addons/button";
@import "addons/clearfix";
@import "addons/font-family";
@import "addons/hide-text";
@import "addons/html5-input-types";
@import "addons/position";
@import "addons/prefixer";
@import "addons/retina-image";
@import "addons/size";
@import "addons/timing-functions";
@import "addons/triangle";

// Soon to be deprecated Mixins
@import "bourbon-deprecated-upcoming";

<===> lib/addons/_button.scss
@mixin button ($style: simple, $base-color: #4294f0) {

  @if type-of($style) == color {
    $base-color: $style;
    $style: simple;
  }

  // Grayscale button
  @if $base-color == grayscale($base-color) {
    @if $style == simple {
      @include simple($base-color, $grayscale: true);
    }

    @else if $style == shiny {
      @include shiny($base-color, $grayscale: true);
    }

    @else if $style == pill {
      @include pill($base-color, $grayscale: true);
    }
  }

  // Colored button
  @else {
    @if $style == simple {
      @include simple($base-color);
    }

    @else if $style == shiny {
      @include shiny($base-color);
    }

    @else if $style == pill {
      @include pill($base-color);
    }
  }

  &:disabled {
    opacity: 0.5;
    cursor: not-allowed;
  }
}


// Simple Button
//************************************************************************//
@mixin simple($base-color, $grayscale: false) {
  $color:         hsl(0, 0, 100%);
  $border:        adjust-color($base-color, $saturation:  9%,  $lightness: -14%);
  $inset-shadow:  adjust-color($base-color, $saturation: -8%,  $lightness:  15%);
  $stop-gradient: adjust-color($base-color, $saturation:  9%,  $lightness: -11%);
  $text-shadow:   adjust-color($base-color, $saturation:  15%, $lightness: -18%);

  @if lightness($base-color) > 70% {
    $color:       hsl(0, 0, 20%);
    $text-shadow: adjust-color($base-color, $saturation: 10%, $lightness: 4%);
  }

  @if $grayscale == true {
    $border:        grayscale($border);
    $inset-shadow:  grayscale($inset-shadow);
    $stop-gradient: grayscale($stop-gradient);
    $text-shadow:   grayscale($text-shadow);
  }

  border: 1px solid $border;
  border-radius: 3px;
  box-shadow: inset 0 1px 0 0 $inset-shadow;
  color: $color;
  display: inline-block;
  font-size: 11px;
  font-weight: bold;
  @include linear-gradient ($base-color, $stop-gradient);
  padding: 7px 18px;
  text-decoration: none;
  text-shadow: 0 1px 0 $text-shadow;
  background-clip: padding-box;

  &:hover:not(:disabled) {
    $base-color-hover:    adjust-color($base-color, $saturation: -4%, $lightness: -5%);
    $inset-shadow-hover:  adjust-color($base-color, $saturation: -7%, $lightness:  5%);
    $stop-gradient-hover: adjust-color($base-color, $saturation:  8%, $lightness: -14%);

    @if $grayscale == true {
      $base-color-hover:    grayscale($base-color-hover);
      $inset-shadow-hover:  grayscale($inset-shadow-hover);
      $stop-gradient-hover: grayscale($stop-gradient-hover);
    }

    box-shadow: inset 0 1px 0 0 $inset-shadow-hover;
    cursor: pointer;
    @include linear-gradient ($base-color-hover, $stop-gradient-hover);
  }

  &:active:not(:disabled) {
    $border-active:       adjust-color($base-color, $saturation: 9%, $lightness: -14%);
    $inset-shadow-active: adjust-color($base-color, $saturation: 7%, $lightness: -17%);

    @if $grayscale == true {
      $border-active:       grayscale($border-active);
      $inset-shadow-active: grayscale($inset-shadow-active);
    }

    border: 1px solid $border-active;
    box-shadow: inset 0 0 8px 4px $inset-shadow-active, inset 0 0 8px 4px $inset-shadow-active, 0 1px 1px 0 #eee;
  }
}


// Shiny Button
//************************************************************************//
@mixin shiny($base-color, $grayscale: false) {
  $color:         hsl(0, 0, 100%);
  $border:        adjust-color($base-color, $red: -117, $green: -111, $blue: -81);
  $border-bottom: adjust-color($base-color, $red: -126, $green: -127, $blue: -122);
  $fourth-stop:   adjust-color($base-color, $red: -79,  $green: -70,  $blue: -46);
  $inset-shadow:  adjust-color($base-color, $red:  37,  $green:  29,  $blue:  12);
  $second-stop:   adjust-color($base-color, $red: -56,  $green: -50,  $blue: -33);
  $text-shadow:   adjust-color($base-color, $red: -140, $green: -141, $blue: -114);
  $third-stop:    adjust-color($base-color, $red: -86,  $green: -75,  $blue: -48);

  @if lightness($base-color) > 70% {
    $color:       hsl(0, 0, 20%);
    $text-shadow: adjust-color($base-color, $saturation: 10%, $lightness: 4%);
  }

  @if $grayscale == true {
    $border:        grayscale($border);
    $border-bottom: grayscale($border-bottom);
    $fourth-stop:   grayscale($fourth-stop);
    $inset-shadow:  grayscale($inset-shadow);
    $second-stop:   grayscale($second-stop);
    $text-shadow:   grayscale($text-shadow);
    $third-stop:    grayscale($third-stop);
  }

  border: 1px solid $border;
  border-bottom: 1px solid $border-bottom;
  border-radius: 5px;
  box-shadow: inset 0 1px 0 0 $inset-shadow;
  color: $color;
  display: inline-block;
  font-size: 14px;
  font-weight: bold;
  @include linear-gradient(top, $base-color 0%, $second-stop 50%, $third-stop 50%, $fourth-stop 100%);
  padding: 8px 20px;
  text-align: center;
  text-decoration: none;
  text-shadow: 0 -1px 1px $text-shadow;

  &:hover:not(:disabled) {
    $first-stop-hover:  adjust-color($base-color, $red: -13, $green: -15, $blue: -18);
    $second-stop-hover: adjust-color($base-color, $red: -66, $green: -62, $blue: -51);
    $third-stop-hover:  adjust-color($base-color, $red: -93, $green: -85, $blue: -66);
    $fourth-stop-hover: adjust-color($base-color, $red: -86, $green: -80, $blue: -63);

    @if $grayscale == true {
      $first-stop-hover:  grayscale($first-stop-hover);
      $second-stop-hover: grayscale($second-stop-hover);
      $third-stop-hover:  grayscale($third-stop-hover);
      $fourth-stop-hover: grayscale($fourth-stop-hover);
    }

    cursor: pointer;
    @include linear-gradient(top, $first-stop-hover  0%,
                                  $second-stop-hover 50%,
                                  $third-stop-hover  50%,
                                  $fourth-stop-hover 100%);
  }

  &:active:not(:disabled) {
    $inset-shadow-active: adjust-color($base-color, $red: -111, $green: -116, $blue: -122);

    @if $grayscale == true {
      $inset-shadow-active: grayscale($inset-shadow-active);
    }

    box-shadow: inset 0 0 20px 0 $inset-shadow-active, 0 1px 0 #fff;
  }
}


// Pill Button
//************************************************************************//
@mixin pill($base-color, $grayscale: false) {
  $color:         hsl(0, 0, 100%);
  $border-bottom: adjust-color($base-color, $hue:  8, $saturation: -11%, $lightness: -26%);
  $border-sides:  adjust-color($base-color, $hue:  4, $saturation: -21%, $lightness: -21%);
  $border-top:    adjust-color($base-color, $hue: -1, $saturation: -30%, $lightness: -15%);
  $inset-shadow:  adjust-color($base-color, $hue: -1, $saturation: -1%,  $lightness:  7%);
  $stop-gradient: adjust-color($base-color, $hue:  8, $saturation:  14%, $lightness: -10%);
  $text-shadow:   adjust-color($base-color, $hue:  5, $saturation: -19%, $lightness: -15%);

  @if lightness($base-color) > 70% {
    $color:       hsl(0, 0, 20%);
    $text-shadow: adjust-color($base-color, $saturation: 10%, $lightness: 4%);
  }

  @if $grayscale == true {
    $border-bottom: grayscale($border-bottom);
    $border-sides:  grayscale($border-sides);
    $border-top:    grayscale($border-top);
    $inset-shadow:  grayscale($inset-shadow);
    $stop-gradient: grayscale($stop-gradient);
    $text-shadow:   grayscale($text-shadow);
  }

  border: 1px solid $border-top;
  border-color: $border-top $border-sides $border-bottom;
  border-radius: 16px;
  box-shadow: inset 0 1px 0 0 $inset-shadow, 0 1px 2px 0 #b3b3b3;
  color: $color;
  display: inline-block;
  font-size: 11px;
  font-weight: normal;
  line-height: 1;
  @include linear-gradient ($base-color, $stop-gradient);
  padding: 5px 16px;
  text-align: center;
  text-decoration: none;
  text-shadow: 0 -1px 1px $text-shadow;
  background-clip: padding-box;

  &:hover:not(:disabled) {
    $base-color-hover:    adjust-color($base-color,                                $lightness: -4.5%);
    $border-bottom:       adjust-color($base-color, $hue:  8, $saturation:  13.5%, $lightness: -32%);
    $border-sides:        adjust-color($base-color, $hue:  4, $saturation: -2%,    $lightness: -27%);
    $border-top:          adjust-color($base-color, $hue: -1, $saturation: -17%,   $lightness: -21%);
    $inset-shadow-hover:  adjust-color($base-color,           $saturation: -1%,    $lightness:  3%);
    $stop-gradient-hover: adjust-color($base-color, $hue:  8, $saturation: -4%,    $lightness: -15.5%);
    $text-shadow-hover:   adjust-color($base-color, $hue:  5, $saturation: -5%,    $lightness: -22%);

    @if $grayscale == true {
      $base-color-hover:    grayscale($base-color-hover);
      $border-bottom:       grayscale($border-bottom);
      $border-sides:        grayscale($border-sides);
      $border-top:          grayscale($border-top);
      $inset-shadow-hover:  grayscale($inset-shadow-hover);
      $stop-gradient-hover: grayscale($stop-gradient-hover);
      $text-shadow-hover:   grayscale($text-shadow-hover);
    }

    border: 1px solid $border-top;
    border-color: $border-top $border-sides $border-bottom;
    box-shadow: inset 0 1px 0 0 $inset-shadow-hover;
    cursor: pointer;
    @include linear-gradient ($base-color-hover, $stop-gradient-hover);
    text-shadow: 0 -1px 1px $text-shadow-hover;
    background-clip: padding-box;
  }

  &:active:not(:disabled) {
    $active-color:         adjust-color($base-color, $hue: 4,  $saturation: -12%,  $lightness: -10%);
    $border-active:        adjust-color($base-color, $hue: 6,  $saturation: -2.5%, $lightness: -30%);
    $border-bottom-active: adjust-color($base-color, $hue: 11, $saturation:  6%,   $lightness: -31%);
    $inset-shadow-active:  adjust-color($base-color, $hue: 9,  $saturation:  2%,   $lightness: -21.5%);
    $text-shadow-active:   adjust-color($base-color, $hue: 5,  $saturation: -12%,  $lightness: -21.5%);

    @if $grayscale == true {
      $active-color:         grayscale($active-color);
      $border-active:        grayscale($border-active);
      $border-bottom-active: grayscale($border-bottom-active);
      $inset-shadow-active:  grayscale($inset-shadow-active);
      $text-shadow-active:   grayscale($text-shadow-active);
    }

    background: $active-color;
    border: 1px solid $border-active;
    border-bottom: 1px solid $border-bottom-active;
    box-shadow: inset 0 0 6px 3px $inset-shadow-active, 0 1px 0 0 #fff;
    text-shadow: 0 -1px 1px $text-shadow-active;
  }
}

<===> lib/addons/_clearfix.scss
// Micro clearfix provides an easy way to contain floats without adding additional markup
//
// Example usage:
//
//    // Contain all floats within .wrapper
//    .wrapper {
//      @include clearfix;
//      .content,
//      .sidebar {
//        float : left;
//      }
//    }

@mixin clearfix {
  *zoom: 1;

  &:before,
  &:after {
    content: " ";
    display: table;
  }

  &:after {
    clear: both;
  }
}

// Acknowledgements
// Micro clearfix: [Nicolas Gallagher](http://nicolasgallagher.com/micro-clearfix-hack/)

<===> lib/addons/_font-family.scss
$georgia: Georgia, Cambria, "Times New Roman", Times, serif;
$helvetica: "Helvetica Neue", Helvetica, Arial, sans-serif;
$lucida-grande: "Lucida Grande", Tahoma, Verdana, Arial, sans-serif;
$monospace: "Bitstream Vera Sans Mono", Consolas, Courier, monospace;
$verdana: Verdana, Geneva, sans-serif;

<===> lib/addons/_hide-text.scss
@mixin hide-text {
  color:            transparent;
  font:             0/0 a;
  text-shadow:      none;
}

<===> lib/addons/_html5-input-types.scss
//************************************************************************//
// Generate a variable ($all-text-inputs) with a list of all html5
// input types that have a text-based input, excluding textarea.
// http://diveintohtml5.org/forms.html
//************************************************************************//
$inputs-list: 'input[type="email"]',
              'input[type="number"]',
              'input[type="password"]',
              'input[type="search"]',
              'input[type="tel"]',
              'input[type="text"]',
              'input[type="url"]',

              // Webkit & Gecko may change the display of these in the future
              'input[type="color"]',
              'input[type="date"]',
              'input[type="datetime"]',
              'input[type="datetime-local"]',
              'input[type="month"]',
              'input[type="time"]',
              'input[type="week"]';

$unquoted-inputs-list: ();
@each $input-type in $inputs-list {
  $unquoted-inputs-list: append($unquoted-inputs-list, unquote($input-type), comma);
}

$all-text-inputs: $unquoted-inputs-list;


// Hover Pseudo-class
//************************************************************************//
$all-text-inputs-hover: ();
@each $input-type in $unquoted-inputs-list {
      $input-type-hover: $input-type + ":hover";
      $all-text-inputs-hover: append($all-text-inputs-hover, $input-type-hover, comma);
}

// Focus Pseudo-class
//************************************************************************//
$all-text-inputs-focus: ();
@each $input-type in $unquoted-inputs-list {
      $input-type-focus: $input-type + ":focus";
      $all-text-inputs-focus: append($all-text-inputs-focus, $input-type-focus, comma);
}

// You must use interpolation on the variable:
// #{$all-text-inputs}
// #{$all-text-inputs-hover}
// #{$all-text-inputs-focus}

// Example
//************************************************************************//
//   #{$all-text-inputs}, textarea {
//     border: 1px solid red;
//   }

<===> lib/addons/_position.scss
@mixin position ($position: relative, $coordinates: 0 0 0 0) {

  @if type-of($position) == list {
    $coordinates: $position;
    $position: relative;
  }

  $top: nth($coordinates, 1);
  $right: nth($coordinates, 2);
  $bottom: nth($coordinates, 3);
  $left: nth($coordinates, 4);

  position: $position;

  @if $top == auto {
    top: $top;
  }
  @else if not(unitless($top)) {
    top: $top;
  }

  @if $right == auto {
    right: $right;
  }
  @else if not(unitless($right)) {
    right: $right;
  }

  @if $bottom == auto {
    bottom: $bottom;
  }
  @else if not(unitless($bottom)) {
    bottom: $bottom;
  }

  @if $left == auto {
    left: $left;
  }
  @else if not(unitless($left)) {
    left: $left;
  }
}

<===> lib/addons/_prefixer.scss
//************************************************************************//
// Example: @include prefixer(border-radius, $radii, webkit ms spec);
//************************************************************************//
$prefix-for-webkit:    true !default;
$prefix-for-mozilla:   true !default;
$prefix-for-microsoft: true !default;
$prefix-for-opera:     true !default;
$prefix-for-spec:      true !default; // required for keyframe mixin

@mixin prefixer ($property, $value, $prefixes) {
  @each $prefix in $prefixes {
    @if $prefix == webkit {
      @if $prefix-for-webkit {
        -webkit-#{$property}: $value;
      }
    }
    @else if $prefix == moz {
      @if $prefix-for-mozilla {
        -moz-#{$property}: $value;
      }
    }
    @else if $prefix == ms {
      @if $prefix-for-microsoft {
        -ms-#{$property}: $value;
      }
    }
    @else if $prefix == o {
      @if $prefix-for-opera {
        -o-#{$property}: $value;
      }
    }
    @else if $prefix == spec {
      @if $prefix-for-spec {
        #{$property}: $value;
      }
    }
    @else  {
      @warn "Unrecognized prefix: #{$prefix}";
    }
  }
}

@mixin disable-prefix-for-all() {
  $prefix-for-webkit:    false;
  $prefix-for-mozilla:   false;
  $prefix-for-microsoft: false;
  $prefix-for-opera:     false;
  $prefix-for-spec:      false;
}

<===> lib/addons/_retina-image.scss
@mixin retina-image($filename, $background-size, $extension: png, $retina-filename: null, $asset-pipeline: false) {
  @if $asset-pipeline {
    background-image: image_url("#{$filename}.#{$extension}");
  }
  @else {
    background-image: url("#{$filename}.#{$extension}");
  }

  @include hidpi {

    @if $asset-pipeline {
      @if $retina-filename {
        background-image: image_url("#{$retina-filename}.#{$extension}");
      }
      @else {
        background-image: image_url("#{$filename}@2x.#{$extension}");
      }
    }

    @else {
      @if $retina-filename {
        background-image: url("#{$retina-filename}.#{$extension}");
      }
      @else {
        background-image: url("#{$filename}@2x.#{$extension}");
      }
    }

    background-size: $background-size;

  }
}

<===> lib/addons/_size.scss
@mixin size($size) {
  @if length($size) == 1 {
    @if $size == auto {
      width:  $size;
      height: $size;
    }

    @else if unitless($size) {
      width:  $size + px;
      height: $size + px;
    }

    @else if not(unitless($size)) {
      width:  $size;
      height: $size;
    }
  }

  // Width x Height
  @if length($size) == 2 {
    $width:  nth($size, 1);
    $height: nth($size, 2);

    @if $width == auto {
      width: $width;
    }
    @else if not(unitless($width)) {
      width: $width;
    }
    @else if unitless($width) {
      width: $width + px;
    }

    @if $height == auto {
      height: $height;
    }
    @else if not(unitless($height)) {
      height: $height;
    }
    @else if unitless($height) {
      height: $height + px;
    }
  }
}

<===> lib/addons/_timing-functions.scss
// CSS cubic-bezier timing functions. Timing functions courtesy of jquery.easie (github.com/jaukia/easie)
// Timing functions are the same as demo'ed here: http://jqueryui.com/demos/effect/easing.html

// EASE IN
$ease-in-quad:      cubic-bezier(0.550,  0.085, 0.680, 0.530);
$ease-in-cubic:     cubic-bezier(0.550,  0.055, 0.675, 0.190);
$ease-in-quart:     cubic-bezier(0.895,  0.030, 0.685, 0.220);
$ease-in-quint:     cubic-bezier(0.755,  0.050, 0.855, 0.060);
$ease-in-sine:      cubic-bezier(0.470,  0.000, 0.745, 0.715);
$ease-in-expo:      cubic-bezier(0.950,  0.050, 0.795, 0.035);
$ease-in-circ:      cubic-bezier(0.600,  0.040, 0.980, 0.335);
$ease-in-back:      cubic-bezier(0.600, -0.280, 0.735, 0.045);

// EASE OUT
$ease-out-quad:     cubic-bezier(0.250,  0.460, 0.450, 0.940);
$ease-out-cubic:    cubic-bezier(0.215,  0.610, 0.355, 1.000);
$ease-out-quart:    cubic-bezier(0.165,  0.840, 0.440, 1.000);
$ease-out-quint:    cubic-bezier(0.230,  1.000, 0.320, 1.000);
$ease-out-sine:     cubic-bezier(0.390,  0.575, 0.565, 1.000);
$ease-out-expo:     cubic-bezier(0.190,  1.000, 0.220, 1.000);
$ease-out-circ:     cubic-bezier(0.075,  0.820, 0.165, 1.000);
$ease-out-back:     cubic-bezier(0.175,  0.885, 0.320, 1.275);

// EASE IN OUT
$ease-in-out-quad:  cubic-bezier(0.455,  0.030, 0.515, 0.955);
$ease-in-out-cubic: cubic-bezier(0.645,  0.045, 0.355, 1.000);
$ease-in-out-quart: cubic-bezier(0.770,  0.000, 0.175, 1.000);
$ease-in-out-quint: cubic-bezier(0.860,  0.000, 0.070, 1.000);
$ease-in-out-sine:  cubic-bezier(0.445,  0.050, 0.550, 0.950);
$ease-in-out-expo:  cubic-bezier(1.000,  0.000, 0.000, 1.000);
$ease-in-out-circ:  cubic-bezier(0.785,  0.135, 0.150, 0.860);
$ease-in-out-back:  cubic-bezier(0.680, -0.550, 0.265, 1.550);

<===> lib/addons/_triangle.scss
@mixin triangle ($size, $color, $direction) {
  height: 0;
  width: 0;

  @if ($direction == up) or ($direction == down) or ($direction == right) or ($direction == left) {
    border-color: transparent;
    border-style: solid;
    border-width: $size / 2;

    @if $direction == up {
      border-bottom-color: $color;

    } @else if $direction == right {
      border-left-color:   $color;

    } @else if $direction == down {
      border-top-color:    $color;

    } @else if $direction == left {
      border-right-color:  $color;
    }
  }

  @else if ($direction == up-right) or ($direction == up-left) {
    border-top: $size solid $color;

    @if $direction == up-right {
      border-left:  $size solid transparent;

    } @else if $direction == up-left {
      border-right: $size solid transparent;
    }
  }

  @else if ($direction == down-right) or ($direction == down-left) {
    border-bottom: $size solid $color;

    @if $direction == down-right {
      border-left:  $size solid transparent;

    } @else if $direction == down-left {
      border-right: $size solid transparent;
    }
  }
}

<===> lib/css3/_animation.scss
// http://www.w3.org/TR/css3-animations/#the-animation-name-property-
// Each of these mixins support comma separated lists of values, which allows different transitions for individual properties to be described in a single style rule. Each value in the list corresponds to the value at that same position in the other properties.

// Official animation shorthand property.
@mixin animation ($animations...) {
  @include prefixer(animation, $animations, webkit moz spec);
}

// Individual Animation Properties
@mixin animation-name ($names...) {
  @include prefixer(animation-name, $names, webkit moz spec);
}


@mixin animation-duration ($times...) {
  @include prefixer(animation-duration, $times, webkit moz spec);
}


@mixin animation-timing-function ($motions...) {
// ease | linear | ease-in | ease-out | ease-in-out
  @include prefixer(animation-timing-function, $motions, webkit moz spec);
}


@mixin animation-iteration-count ($values...) {
// infinite | <number>
  @include prefixer(animation-iteration-count, $values, webkit moz spec);
}


@mixin animation-direction ($directions...) {
// normal | alternate
  @include prefixer(animation-direction, $directions, webkit moz spec);
}


@mixin animation-play-state ($states...) {
// running | paused
  @include prefixer(animation-play-state, $states, webkit moz spec);
}


@mixin animation-delay ($times...) {
  @include prefixer(animation-delay, $times, webkit moz spec);
}


@mixin animation-fill-mode ($modes...) {
// none | forwards | backwards | both
  @include prefixer(animation-fill-mode, $modes, webkit moz spec);
}

<===> lib/css3/_appearance.scss
@mixin appearance ($value) {
  @include prefixer(appearance, $value, webkit moz ms o spec);
}

<===> lib/css3/_backface-visibility.scss
//************************************************************************//
// Backface-visibility mixin
//************************************************************************//
@mixin backface-visibility($visibility) {
  @include prefixer(backface-visibility, $visibility, webkit spec);
}

<===> lib/css3/_background-image.scss
//************************************************************************//
// Background-image property for adding multiple background images with
// gradients, or for stringing multiple gradients together.
//************************************************************************//

@mixin background-image($images...) {
  background-image: _add-prefix($images, webkit);
  background-image: _add-prefix($images);
}

@function _add-prefix($images, $vendor: false) {
  $images-prefixed: ();
  $gradient-positions: false;
  @for $i from 1 through length($images) {
    $type: type-of(nth($images, $i)); // Get type of variable - List or String

    // If variable is a list - Gradient
    @if $type == list {
      $gradient-type: nth(nth($images, $i), 1); // linear or radial
      $gradient-pos: null;
      $gradient-args: null;

      @if ($gradient-type == linear) or ($gradient-type == radial) {
        $gradient-pos:  nth(nth($images, $i), 2); // Get gradient position
        $gradient-args: nth(nth($images, $i), 3); // Get actual gradient (red, blue)
      }
      @else {
        $gradient-args: nth(nth($images, $i), 2); // Get actual gradient (red, blue)
      }

      $gradient-positions: _gradient-positions-parser($gradient-type, $gradient-pos);
      $gradient: _render-gradients($gradient-positions, $gradient-args, $gradient-type, $vendor);
      $images-prefixed: append($images-prefixed, $gradient, comma);
    }
    // If variable is a string - Image
    @else if $type == string {
      $images-prefixed: join($images-prefixed, nth($images, $i), comma);
    }
  }
  @return $images-prefixed;
}

//Examples:
  //@include background-image(linear-gradient(top, orange, red));
  //@include background-image(radial-gradient(50% 50%, cover circle, orange, red));
  //@include background-image(url("/images/a.png"), linear-gradient(orange, red));
  //@include background-image(url("image.png"), linear-gradient(orange, red), url("image.png"));
  //@include background-image(linear-gradient(hsla(0, 100%, 100%, 0.25) 0%, hsla(0, 100%, 100%, 0.08) 50%, transparent 50%), linear-gradient(orange, red));

<===> lib/css3/_background.scss
//************************************************************************//
// Background property for adding multiple backgrounds using shorthand
// notation.
//************************************************************************//

@mixin background(
  $background-1       , $background-2: false,
  $background-3: false, $background-4: false,
  $background-5: false, $background-6: false,
  $background-7: false, $background-8: false,
  $background-9: false, $background-10: false,
  $fallback: false
) {
  $backgrounds: compact($background-1, $background-2,
                $background-3, $background-4,
                $background-5, $background-6,
                $background-7, $background-8,
                $background-9, $background-10);

  $fallback-color: false;
  @if (type-of($fallback) == color) or ($fallback == "transparent") {
    $fallback-color: $fallback;
  }
  @else {
    $fallback-color: _extract-background-color($backgrounds);
  }

  @if $fallback-color {
    background-color: $fallback-color;
  }
  background: _background-add-prefix($backgrounds, webkit);
  background: _background-add-prefix($backgrounds);
}

@function _extract-background-color($backgrounds) {
  $final-bg-layer: nth($backgrounds, length($backgrounds));
  @if type-of($final-bg-layer) == list {
    @for $i from 1 through length($final-bg-layer) {
      $value: nth($final-bg-layer, $i);
      @if type-of($value) == color {
        @return $value;
      }
    }
  }
  @return false;
}

@function _background-add-prefix($backgrounds, $vendor: false) {
  $backgrounds-prefixed: ();

  @for $i from 1 through length($backgrounds) {
    $shorthand: nth($backgrounds, $i); // Get member for current index
    $type: type-of($shorthand); // Get type of variable - List (gradient) or String (image)

    // If shorthand is a list (gradient)
    @if $type == list {
      $first-member: nth($shorthand, 1); // Get first member of shorthand

      // Linear Gradient
      @if index(linear radial, nth($first-member, 1)) {
        $gradient-type: nth($first-member, 1); // linear || radial
        $gradient-args:      false;
        $gradient-positions: false;
        $shorthand-start:    false;
        @if type-of($first-member) == list { // Linear gradient plus additional shorthand values - lg(red,orange)repeat,...
          $gradient-positions: nth($first-member, 2);
          $gradient-args:      nth($first-member, 3);
          $shorthand-start: 2;
        }
        @else { // Linear gradient only - lg(red,orange),...
          $gradient-positions: nth($shorthand, 2);
          $gradient-args:      nth($shorthand, 3); // Get gradient (red, blue)
        }

        $gradient-positions: _gradient-positions-parser($gradient-type, $gradient-positions);
        $gradient: _render-gradients($gradient-positions, $gradient-args, $gradient-type, $vendor);

        // Append any additional shorthand args to gradient
        @if $shorthand-start {
          @for $j from $shorthand-start through length($shorthand) {
            $gradient: join($gradient, nth($shorthand, $j), space);
          }
        }
        $backgrounds-prefixed: append($backgrounds-prefixed, $gradient, comma);
      }
      // Image with additional properties
      @else {
        $backgrounds-prefixed: append($backgrounds-prefixed, $shorthand, comma);
      }
    }
    // If shorthand is a simple string (color or image)
    @else if $type == string {
      $backgrounds-prefixed: join($backgrounds-prefixed, $shorthand, comma);
    }
  }
  @return $backgrounds-prefixed;
}

//Examples:
  //@include background(linear-gradient(top, orange, red));
  //@include background(radial-gradient(circle at 40% 40%, orange, red));
  //@include background(url("/images/a.png") no-repeat, linear-gradient(orange, red));
  //@include background(url("image.png") center center, linear-gradient(orange, red), url("image.png"));

<===> lib/css3/_border-image.scss
@mixin border-image($images) {
  -webkit-border-image: _border-add-prefix($images, webkit);
     -moz-border-image: _border-add-prefix($images, moz);
       -o-border-image: _border-add-prefix($images, o);
          border-image: _border-add-prefix($images);
}

@function _border-add-prefix($images, $vendor: false) {
  $border-image: null;
  $images-type:  type-of(nth($images, 1));
  $first-var:    nth(nth($images, 1), 1);          // Get type of Gradient (Linear || radial)

  // If input is a gradient
  @if $images-type == string {
    @if ($first-var == "linear") or ($first-var == "radial") {
      $gradient-type: nth($images, 1);           // Get type of gradient (linear || radial)
      $gradient-pos:  nth($images, 2);           // Get gradient position
      $gradient-args: nth($images, 3);           // Get actual gradient (red, blue)
      $gradient-positions: _gradient-positions-parser($gradient-type, $gradient-pos);
      $border-image:  _render-gradients($gradient-positions, $gradient-args, $gradient-type, $vendor);
    }
    // If input is a URL
    @else {
      $border-image: $images;
    }
  }
  // If input is gradient or url + additional args
  @else if $images-type == list {
    $type: type-of(nth($images, 1));           // Get type of variable - List or String

    // If variable is a list - Gradient
    @if $type == list {
      $gradient: nth($images, 1);
      $gradient-type: nth($gradient, 1);           // Get type of gradient (linear || radial)
      $gradient-pos:  nth($gradient, 2);           // Get gradient position
      $gradient-args: nth($gradient, 3);           // Get actual gradient (red, blue)
      $gradient-positions: _gradient-positions-parser($gradient-type, $gradient-pos);
      $border-image:  _render-gradients($gradient-positions, $gradient-args, $gradient-type, $vendor);

      @for $i from 2 through length($images) {
        $border-image: append($border-image, nth($images, $i));
      }
    }
  }
  @return $border-image;
}

//Examples:
// @include border-image(url("image.png"));
// @include border-image(url("image.png") 20 stretch);
// @include border-image(linear-gradient(45deg, orange, yellow));
// @include border-image(linear-gradient(45deg, orange, yellow) stretch);
// @include border-image(linear-gradient(45deg, orange, yellow) 20 30 40 50 stretch round);
// @include border-image(radial-gradient(top, cover, orange, yellow, orange));


<===> lib/css3/_border-radius.scss
//************************************************************************//
// Shorthand Border-radius mixins
//************************************************************************//
@mixin border-top-radius($radii) {
  @include prefixer(border-top-left-radius, $radii, spec);
  @include prefixer(border-top-right-radius, $radii, spec);
}

@mixin border-bottom-radius($radii) {
  @include prefixer(border-bottom-left-radius, $radii, spec);
  @include prefixer(border-bottom-right-radius, $radii, spec);
}

@mixin border-left-radius($radii) {
  @include prefixer(border-top-left-radius, $radii, spec);
  @include prefixer(border-bottom-left-radius, $radii, spec);
}

@mixin border-right-radius($radii) {
  @include prefixer(border-top-right-radius, $radii, spec);
  @include prefixer(border-bottom-right-radius, $radii, spec);
}

<===> lib/css3/_box-sizing.scss
@mixin box-sizing ($box) {
//  content-box | border-box | inherit
  @include prefixer(box-sizing, $box, webkit moz spec);
}

<===> lib/css3/_columns.scss
@mixin columns($arg: auto) {
// <column-count> || <column-width>
  @include prefixer(columns, $arg, webkit moz spec);
}

@mixin column-count($int: auto) {
// auto || integer
  @include prefixer(column-count, $int, webkit moz spec);
}

@mixin column-gap($length: normal) {
// normal || length
  @include prefixer(column-gap, $length, webkit moz spec);
}

@mixin column-fill($arg: auto) {
// auto || length
  @include prefixer(columns-fill, $arg, webkit moz spec);
}

@mixin column-rule($arg) {
// <border-width> || <border-style> || <color>
  @include prefixer(column-rule, $arg, webkit moz spec);
}

@mixin column-rule-color($color) {
  @include prefixer(column-rule-color, $color, webkit moz spec);
}

@mixin column-rule-style($style: none) {
// none | hidden | dashed | dotted | double | groove | inset | inset | outset | ridge | solid
  @include prefixer(column-rule-style, $style, webkit moz spec);
}

@mixin column-rule-width ($width: none) {
  @include prefixer(column-rule-width, $width, webkit moz spec);
}

@mixin column-span($arg: none) {
// none || all
  @include prefixer(column-span, $arg, webkit moz spec);
}

@mixin column-width($length: auto) {
// auto || length
  @include prefixer(column-width, $length, webkit moz spec);
}

<===> lib/css3/_flex-box.scss
// CSS3 Flexible Box Model and property defaults

// Custom shorthand notation for flexbox
@mixin box($orient: inline-axis, $pack: start, $align: stretch) {
  @include display-box;
  @include box-orient($orient);
  @include box-pack($pack);
  @include box-align($align);
}

@mixin display-box {
  display: -webkit-box;
  display: -moz-box;
  display: box;
}

@mixin box-orient($orient: inline-axis) {
// horizontal|vertical|inline-axis|block-axis|inherit
  @include prefixer(box-orient, $orient, webkit moz spec);
}

@mixin box-pack($pack: start) {
// start|end|center|justify
  @include prefixer(box-pack, $pack, webkit moz spec);
}

@mixin box-align($align: stretch) {
// start|end|center|baseline|stretch
  @include prefixer(box-align, $align, webkit moz spec);
}

@mixin box-direction($direction: normal) {
// normal|reverse|inherit
  @include prefixer(box-direction, $direction, webkit moz spec);
}

@mixin box-lines($lines: single) {
// single|multiple
  @include prefixer(box-lines, $lines, webkit moz spec);
}

@mixin box-ordinal-group($int: 1) {
  @include prefixer(box-ordinal-group, $int, webkit moz spec);
}

@mixin box-flex($value: 0.0) {
  @include prefixer(box-flex, $value, webkit moz spec);
}

@mixin box-flex-group($int: 1) {
  @include prefixer(box-flex-group, $int, webkit moz spec);
}

<===> lib/css3/_font-face.scss
// Order of the includes matters, and it is: normal, bold, italic, bold+italic.

@mixin font-face($font-family, $file-path, $weight: normal, $style: normal, $asset-pipeline: false ) {
  @font-face {
    font-family: $font-family;
    font-weight: $weight;
    font-style: $style;

    @if $asset-pipeline == true {
      src: font-url('#{$file-path}.eot');
      src: font-url('#{$file-path}.eot?#iefix')          format('embedded-opentype'),
           font-url('#{$file-path}.woff')                format('woff'),
           font-url('#{$file-path}.ttf')                 format('truetype'),
           font-url('#{$file-path}.svg##{$font-family}') format('svg');
    } @else {
      src: url('#{$file-path}.eot');
      src: url('#{$file-path}.eot?#iefix')               format('embedded-opentype'),
           url('#{$file-path}.woff')                     format('woff'),
           url('#{$file-path}.ttf')                      format('truetype'),
           url('#{$file-path}.svg##{$font-family}')      format('svg');
    }
  }
}

<===> lib/css3/_hidpi-media-query.scss
// HiDPI mixin. Default value set to 1.3 to target Google Nexus 7 (http://bjango.com/articles/min-device-pixel-ratio/)
@mixin hidpi($ratio: 1.3) {
  @media only screen and (-webkit-min-device-pixel-ratio: $ratio),
  only screen and (min--moz-device-pixel-ratio: $ratio),
  only screen and (-o-min-device-pixel-ratio: #{$ratio}/1),
  only screen and (min-resolution: #{round($ratio*96)}dpi),
  only screen and (min-resolution: #{$ratio}dppx) {
    @content;
  }
}

<===> lib/css3/_image-rendering.scss
@mixin image-rendering ($mode:optimizeQuality) {

  @if ($mode == optimize-contrast) {
      image-rendering: -moz-crisp-edges;
      image-rendering: -o-crisp-edges;
      image-rendering: -webkit-optimize-contrast;
      image-rendering: optimize-contrast;
  }

  @else {
      image-rendering: $mode;
  }
}

<===> lib/css3/_inline-block.scss
// Legacy support for inline-block in IE7 (maybe IE6)
@mixin inline-block {
  display: inline-block;
  vertical-align: baseline;
  zoom: 1;
  *display: inline;
  *vertical-align: auto;
}

<===> lib/css3/_keyframes.scss
// Adds keyframes blocks for supported prefixes, removing redundant prefixes in the block's content
@mixin keyframes($name) {
  $original-prefix-for-webkit:    $prefix-for-webkit;
  $original-prefix-for-mozilla:   $prefix-for-mozilla;
  $original-prefix-for-microsoft: $prefix-for-microsoft;
  $original-prefix-for-opera:     $prefix-for-opera;
  $original-prefix-for-spec:      $prefix-for-spec;

  @if $original-prefix-for-webkit {
    @include disable-prefix-for-all();
    $prefix-for-webkit: true;
    #{"@-webkit-keyframes"} #{$name} {
      @content;
    }
  }
  @if $original-prefix-for-mozilla {
    @include disable-prefix-for-all();
    $prefix-for-mozilla: true;
    #{"@-moz-keyframes"} #{$name} {
      @content;
    }
  }
  @if $original-prefix-for-opera {
    @include disable-prefix-for-all();
    $prefix-for-opera: true;
    #{"@-o-keyframes"} #{$name} {
      @content;
    }
  }
  @if $original-prefix-for-spec {
    @include disable-prefix-for-all();
    $prefix-for-spec: true;
    #{"@keyframes"} #{$name} {
      @content;
    }
  }

  $prefix-for-webkit:    $original-prefix-for-webkit;
  $prefix-for-mozilla:   $original-prefix-for-mozilla;
  $prefix-for-microsoft: $original-prefix-for-microsoft;
  $prefix-for-opera:     $original-prefix-for-opera;
  $prefix-for-spec:      $original-prefix-for-spec;
}

<===> lib/css3/_linear-gradient.scss
@mixin linear-gradient($pos, $G1, $G2: false,
                       $G3: false, $G4: false,
                       $G5: false, $G6: false,
                       $G7: false, $G8: false,
                       $G9: false, $G10: false,
                       $deprecated-pos1: left top,
                       $deprecated-pos2: left bottom,
                       $fallback: false) {
  // Detect what type of value exists in $pos
  $pos-type: type-of(nth($pos, 1));
  $pos-spec: null;
  $pos-degree: null;

  // If $pos is missing from mixin, reassign vars and add default position
  @if ($pos-type == color) or (nth($pos, 1) == "transparent")  {
    $G10: $G9; $G9: $G8; $G8: $G7; $G7: $G6; $G6: $G5;
     $G5: $G4; $G4: $G3; $G3: $G2; $G2: $G1; $G1: $pos;
     $pos: null;
  }

  @if $pos {
    $positions: _linear-positions-parser($pos);
    $pos-degree: nth($positions, 1);
    $pos-spec:   nth($positions, 2);
  }

  $full: compact($G1, $G2, $G3, $G4, $G5, $G6, $G7, $G8, $G9, $G10);

  // Set $G1 as the default fallback color
  $fallback-color: nth($G1, 1);

  // If $fallback is a color use that color as the fallback color
  @if (type-of($fallback) == color) or ($fallback == "transparent") {
    $fallback-color: $fallback;
  }

  background-color: $fallback-color;
  background-image: _deprecated-webkit-gradient(linear, $deprecated-pos1, $deprecated-pos2, $full); // Safari <= 5.0
  background-image: -webkit-linear-gradient($pos-degree $full); // Safari 5.1+, Chrome
  background-image: unquote("linear-gradient(#{$pos-spec}#{$full})");
}

<===> lib/css3/_perspective.scss
@mixin perspective($depth: none) {
  // none | <length>
  @include prefixer(perspective, $depth, webkit moz spec);
}

@mixin perspective-origin($value: 50% 50%) {
  @include prefixer(perspective-origin, $value, webkit moz spec);
}

<===> lib/css3/_placeholder.scss
$placeholders: '-webkit-input-placeholder',
               '-moz-placeholder',
               '-ms-input-placeholder';

@mixin placeholder {
  @each $placeholder in $placeholders {
    @if $placeholder == "-webkit-input-placeholder" {
      &::#{$placeholder} {
        @content;
      }
    }
    @else if $placeholder == "-moz-placeholder" {
      // FF 18-
      &:#{$placeholder} {
        @content;
      }

      // FF 19+
      &::#{$placeholder} {
        @content;
      }
    }
    @else {
      &:#{$placeholder} {
        @content;
      }
    }
  }
}

<===> lib/css3/_radial-gradient.scss
// Requires Sass 3.1+
@mixin radial-gradient($G1,        $G2,
                       $G3: false, $G4: false,
                       $G5: false, $G6: false,
                       $G7: false, $G8: false,
                       $G9: false, $G10: false,
                       $pos: null,
                       $shape-size: null,
                       $deprecated-pos1: center center,
                       $deprecated-pos2: center center,
                       $deprecated-radius1: 0,
                       $deprecated-radius2: 460,
                       $fallback: false) {

  $data: _radial-arg-parser($G1, $G2, $pos, $shape-size);
  $G1:  nth($data, 1);
  $G2:  nth($data, 2);
  $pos: nth($data, 3);
  $shape-size: nth($data, 4);

  $full: compact($G1, $G2, $G3, $G4, $G5, $G6, $G7, $G8, $G9, $G10);

  // Strip deprecated cover/contain for spec
  $shape-size-spec: _shape-size-stripper($shape-size);

  // Set $G1 as the default fallback color
  $first-color: nth($full, 1);
  $fallback-color: nth($first-color, 1);

  @if (type-of($fallback) == color) or ($fallback == "transparent") {
    $fallback-color: $fallback;
  }

  // Add Commas and spaces
  $shape-size: if($shape-size, '#{$shape-size}, ', null);
  $pos:        if($pos, '#{$pos}, ', null);
  $pos-spec:   if($pos, 'at #{$pos}', null);
  $shape-size-spec: if(($shape-size-spec != ' ') and ($pos == null), '#{$shape-size-spec}, ', '#{$shape-size-spec} ');

  background-color:  $fallback-color;
  background-image: _deprecated-webkit-gradient(radial, $deprecated-pos1, $deprecated-pos2, $full, $deprecated-radius1, $deprecated-radius2); // Safari <= 5.0 && IOS 4
  background-image: -webkit-radial-gradient(unquote(#{$pos}#{$shape-size}#{$full}));
  background-image: unquote("radial-gradient(#{$shape-size-spec}#{$pos-spec}#{$full})");
}

<===> lib/css3/_transform.scss
@mixin transform($property: none) {
//  none | <transform-function>
  @include prefixer(transform, $property, webkit moz ms o spec);
}

@mixin transform-origin($axes: 50%) {
// x-axis - left | center | right  | length | %
// y-axis - top  | center | bottom | length | %
// z-axis -                          length
  @include prefixer(transform-origin, $axes, webkit moz ms o spec);
}

@mixin transform-style ($style: flat) {
  @include prefixer(transform-style, $style, webkit moz ms o spec);
}

<===> lib/css3/_transition.scss
// Shorthand mixin. Supports multiple parentheses-deliminated values for each variable.
// Example: @include transition (all, 2.0s, ease-in-out);
//          @include transition ((opacity, width), (1.0s, 2.0s), ease-in, (0, 2s));
//          @include transition ($property:(opacity, width), $delay: (1.5s, 2.5s));

@mixin transition ($properties...) {
  @if length($properties) >= 1 {
    @include prefixer(transition, $properties, webkit moz spec);
  }

  @else {
    $properties: all 0.15s ease-out 0;
    @include prefixer(transition, $properties, webkit moz spec);
  }
}

@mixin transition-property ($properties...) {
   -webkit-transition-property: transition-property-names($properties, 'webkit');
      -moz-transition-property: transition-property-names($properties, 'moz');
           transition-property: transition-property-names($properties, false);
}

@mixin transition-duration ($times...) {
  @include prefixer(transition-duration, $times, webkit moz spec);
}

@mixin transition-timing-function ($motions...) {
// ease | linear | ease-in | ease-out | ease-in-out | cubic-bezier()
  @include prefixer(transition-timing-function, $motions, webkit moz spec);
}

@mixin transition-delay ($times...) {
  @include prefixer(transition-delay, $times, webkit moz spec);
}

<===> lib/css3/_user-select.scss
@mixin user-select($arg: none) {
  @include prefixer(user-select, $arg, webkit moz ms spec);
}

<===> lib/functions/_compact.scss
// Remove `false` values from a list

@function compact($vars...) {
  $list: ();
  @each $var in $vars {
    @if $var {
      $list: append($list, $var, comma);
    }
  }
  @return $list;
}

<===> lib/functions/_flex-grid.scss
// Flexible grid
@function flex-grid($columns, $container-columns: $fg-max-columns) {
  $width: $columns * $fg-column + ($columns - 1) * $fg-gutter;
  $container-width: $container-columns * $fg-column + ($container-columns - 1) * $fg-gutter;
  @return percentage($width / $container-width);
}

// Flexible gutter
@function flex-gutter($container-columns: $fg-max-columns, $gutter: $fg-gutter) {
  $container-width: $container-columns * $fg-column + ($container-columns - 1) * $fg-gutter;
  @return percentage($gutter / $container-width);
}

// The $fg-column, $fg-gutter and $fg-max-columns variables must be defined in your base stylesheet to properly use the flex-grid function.
// This function takes the fluid grid equation (target / context = result) and uses columns to help define each.
//
// The calculation presumes that your column structure will be missing the last gutter:
//
//   -- column -- gutter -- column -- gutter -- column
//
//  $fg-column: 60px;             // Column Width
//  $fg-gutter: 25px;             // Gutter Width
//  $fg-max-columns: 12;          // Total Columns For Main Container
//
//  div {
//    width: flex-grid(4);        // returns (315px / 995px) = 31.65829%;
//    margin-left: flex-gutter(); // returns (25px / 995px) = 2.51256%;
//
//    p {
//      width: flex-grid(2, 4);  // returns (145px / 315px) = 46.031746%;
//      float: left;
//      margin: flex-gutter(4);  // returns (25px / 315px) = 7.936508%;
//    }
//
//    blockquote {
//      float: left;
//      width: flex-grid(2, 4); // returns (145px / 315px) = 46.031746%;
//    }
//  }
<===> lib/functions/_grid-width.scss
@function grid-width($n) {
  @return $n * $gw-column + ($n - 1) * $gw-gutter;
}

// The $gw-column and $gw-gutter variables must be defined in your base stylesheet to properly use the grid-width function.
//
//  $gw-column: 100px;         // Column Width
//  $gw-gutter: 40px;          // Gutter Width
//
//  div {
//    width: grid-width(4);    // returns 520px;
//    margin-left: $gw-gutter; // returns 40px;
//  }

<===> lib/functions/_linear-gradient.scss
@function linear-gradient($pos, $gradients...) {
  $type: linear;
  $pos-type: type-of(nth($pos, 1));

  // if $pos doesn't exist, fix $gradient
  @if ($pos-type == color) or (nth($pos, 1) == "transparent")  {
    $gradients: zip($pos $gradients);
    $pos: false;
  }

  $type-gradient: $type, $pos, $gradients;
  @return $type-gradient;
}

<===> lib/functions/_modular-scale.scss
@function modular-scale($value, $increment, $ratio) {
  @if $increment > 0 {
    @for $i from 1 through $increment {
      $value: ($value * $ratio);
    }
  }

  @if $increment < 0 {
    $increment: abs($increment);
    @for $i from 1 through $increment {
      $value: ($value / $ratio);
    }
  }

  @return $value;
}

//  div {
//                     Increment Up GR with positive value
//   font-size:        modular-scale(14px,   1, 1.618); // returns: 22.652px
//
//                     Increment Down GR with negative value
//   font-size:        modular-scale(14px,  -1, 1.618); // returns: 8.653px
//
//                     Can be used with ceil(round up) or floor(round down)
//   font-size: floor( modular-scale(14px, 1, 1.618) ); // returns: 22px
//   font-size:  ceil( modular-scale(14px, 1, 1.618) ); // returns: 23px
//  }
//
// modularscale.com

@function golden-ratio($value, $increment) {
  @return modular-scale($value, $increment, 1.618)
}

//  div {
//    font-size: golden-ratio(14px, 1); // returns: 22.652px
//  }
//
// goldenratiocalculator.com

<===> lib/functions/_px-to-em.scss
// Convert pixels to ems
// eg. for a relational value of 12px write em(12) when the parent is 16px
// if the parent is another value say 24px write em(12, 24)

@function em($pxval, $base: 16) {
  @return ($pxval / $base) * 1em;
}


<===> lib/functions/_radial-gradient.scss
// This function is required and used by the background-image mixin.
@function radial-gradient($G1,        $G2,
                       $G3: false, $G4: false,
                       $G5: false, $G6: false,
                       $G7: false, $G8: false,
                       $G9: false, $G10: false,
                       $pos: null,
                       $shape-size: null) {

  $data: _radial-arg-parser($G1, $G2, $pos, $shape-size);
  $G1:  nth($data, 1);
  $G2:  nth($data, 2);
  $pos: nth($data, 3);
  $shape-size: nth($data, 4);

  $type: radial;
  $gradient: compact($G1, $G2, $G3, $G4, $G5, $G6, $G7, $G8, $G9, $G10);

  $type-gradient: $type, $shape-size $pos, $gradient;
  @return $type-gradient;
}


<===> lib/functions/_tint-shade.scss
// Add percentage of white to a color
@function tint($color, $percent){
  @return mix(white, $color, $percent);
}

// Add percentage of black to a color
@function shade($color, $percent){
  @return mix(black, $color, $percent);
}

<===> lib/functions/_transition-property-name.scss
// Return vendor-prefixed property names if appropriate
// Example: transition-property-names((transform, color, background), moz) -> -moz-transform, color, background
//************************************************************************//
@function transition-property-names($props, $vendor: false) {
	$new-props: ();

	@each $prop in $props {
		$new-props: append($new-props, transition-property-name($prop, $vendor), comma);
	}

	@return $new-props;
}

@function transition-property-name($prop, $vendor: false) {
	// put other properties that need to be prefixed here aswell
	@if $vendor and $prop == transform {
		@return unquote('-'+$vendor+'-'+$prop);
	}
	@else {
		@return $prop;
	}
}
<===> lib/helpers/_deprecated-webkit-gradient.scss
// Render Deprecated Webkit Gradient - Linear || Radial
//************************************************************************//
@function _deprecated-webkit-gradient($type,
                                     $deprecated-pos1, $deprecated-pos2,
                                     $full,
                                     $deprecated-radius1: false, $deprecated-radius2: false) {
  $gradient-list: ();
  $gradient: false;
  $full-length: length($full);
  $percentage: false;
  $gradient-type: $type;

  @for $i from 1 through $full-length {
    $gradient: nth($full, $i);

    @if length($gradient) == 2 {
      $color-stop: color-stop(nth($gradient, 2), nth($gradient, 1));
      $gradient-list: join($gradient-list, $color-stop, comma);
    }
    @else if $gradient != null {
      @if $i == $full-length {
        $percentage: 100%;
      }
      @else {
        $percentage: ($i - 1) * (100 / ($full-length - 1)) + "%";
      }
      $color-stop: color-stop(unquote($percentage), $gradient);
      $gradient-list: join($gradient-list, $color-stop, comma);
    }
  }

  @if $type == radial {
    $gradient: -webkit-gradient(radial, $deprecated-pos1, $deprecated-radius1, $deprecated-pos2, $deprecated-radius2, $gradient-list);
  }
  @else if $type == linear {
    $gradient: -webkit-gradient(linear, $deprecated-pos1, $deprecated-pos2, $gradient-list);
  }
  @return $gradient;
}

<===> lib/helpers/_gradient-positions-parser.scss
@function _gradient-positions-parser($gradient-type, $gradient-positions) {
  @if $gradient-positions
  and ($gradient-type == linear)
  and (type-of($gradient-positions) != color) {
    $gradient-positions: _linear-positions-parser($gradient-positions);
  }
  @else if $gradient-positions
  and ($gradient-type == radial)
  and (type-of($gradient-positions) != color) {
    $gradient-positions: _radial-positions-parser($gradient-positions);
  }
  @return $gradient-positions;
}

<===> lib/helpers/_linear-positions-parser.scss
@function _linear-positions-parser($pos) {
  $type: type-of(nth($pos, 1));
  $spec: null;
  $degree: null;
  $side: null;
  $corner: null;
  $length: length($pos);
  // Parse Side and corner positions
  @if ($length > 1) {
    @if nth($pos, 1) == "to" { // Newer syntax
      $side: nth($pos, 2);

      @if $length == 2 { // eg. to top
        // Swap for backwards compatability
        $degree: _position-flipper(nth($pos, 2));
      }
      @else if $length == 3 { // eg. to top left
        $corner: nth($pos, 3);
      }
    }
    @else if $length == 2 { // Older syntax ("top left")
      $side: _position-flipper(nth($pos, 1));
      $corner: _position-flipper(nth($pos, 2));
    }

    @if ("#{$side} #{$corner}" == "left top") or ("#{$side} #{$corner}" == "top left") {
      $degree: _position-flipper(#{$side}) _position-flipper(#{$corner});
    }
    @else if ("#{$side} #{$corner}" == "right top") or ("#{$side} #{$corner}" == "top right") {
      $degree: _position-flipper(#{$side}) _position-flipper(#{$corner});
    }
    @else if ("#{$side} #{$corner}" == "right bottom") or ("#{$side} #{$corner}" == "bottom right") {
      $degree: _position-flipper(#{$side}) _position-flipper(#{$corner});
    }
    @else if ("#{$side} #{$corner}" == "left bottom") or ("#{$side} #{$corner}" == "bottom left") {
      $degree: _position-flipper(#{$side}) _position-flipper(#{$corner});
    }
    $spec: to $side $corner;
  }
  @else if $length == 1 {
    // Swap for backwards compatability
    @if $type == string {
      $degree: $pos;
      $spec: to _position-flipper($pos);
    }
    @else {
      $degree: -270 - $pos; //rotate the gradient opposite from spec
      $spec: $pos;
    }
  }
  $degree: unquote($degree + ",");
  $spec:   unquote($spec + ",");
  @return $degree $spec;
}

@function _position-flipper($pos) {
 @return if($pos == left, right, null)
         if($pos == right, left, null)
         if($pos == top, bottom, null)
         if($pos == bottom, top, null);
}

<===> lib/helpers/_radial-arg-parser.scss
@function _radial-arg-parser($G1, $G2, $pos, $shape-size) {
  @each $value in $G1, $G2 {
    $first-val: nth($value, 1);
    $pos-type:  type-of($first-val);
    $spec-at-index: null;

    // Determine if spec was passed to mixin
    @if type-of($value) == list {
      $spec-at-index: if(index($value, at), index($value, at), false);
    }
    @if $spec-at-index {
      @if $spec-at-index > 1 {
        @for $i from 1 through ($spec-at-index - 1) {
          $shape-size: $shape-size nth($value, $i);
        }
        @for $i from ($spec-at-index + 1) through length($value) {
          $pos: $pos nth($value, $i);
        }
      }
      @else if $spec-at-index == 1 {
        @for $i from ($spec-at-index + 1) through length($value) {
          $pos: $pos nth($value, $i);
        }
      }
      $G1: false;
    }

    // If not spec calculate correct values
    @else {
      @if ($pos-type != color) or ($first-val != "transparent") {
        @if ($pos-type == number)
        or ($first-val == "center")
        or ($first-val == "top")
        or ($first-val == "right")
        or ($first-val == "bottom")
        or ($first-val == "left") {

          $pos: $value;

          @if $pos == $G1 {
            $G1: false;
          }
        }

        @else if
           ($first-val == "ellipse")
        or ($first-val == "circle")
        or ($first-val == "closest-side")
        or ($first-val == "closest-corner")
        or ($first-val == "farthest-side")
        or ($first-val == "farthest-corner")
        or ($first-val == "contain")
        or ($first-val == "cover") {

          $shape-size: $value;

          @if $value == $G1 {
            $G1: false;
          }

          @else if $value == $G2 {
            $G2: false;
          }
        }
      }
    }
  }
  @return $G1, $G2, $pos, $shape-size;
}

<===> lib/helpers/_radial-positions-parser.scss
@function _radial-positions-parser($gradient-pos) {
  $shape-size: nth($gradient-pos, 1);
  $pos:        nth($gradient-pos, 2);
  $shape-size-spec: _shape-size-stripper($shape-size);

  $pre-spec: unquote(if($pos, "#{$pos}, ", null))
             unquote(if($shape-size, "#{$shape-size},", null));
  $pos-spec: if($pos, "at #{$pos}", null);

  $spec: "#{$shape-size-spec} #{$pos-spec}";

  // Add comma
  @if ($spec != '  ') {
    $spec: "#{$spec},"
  }

  @return $pre-spec $spec;
}

<===> lib/helpers/_render-gradients.scss
// User for linear and radial gradients within background-image or border-image properties

@function _render-gradients($gradient-positions, $gradients, $gradient-type, $vendor: false) {
  $pre-spec: null;
  $spec: null;
  $vendor-gradients: null;
  @if $gradient-type == linear {
    @if $gradient-positions {
      $pre-spec: nth($gradient-positions, 1);
      $spec:     nth($gradient-positions, 2);
    }
  }
  @else if $gradient-type == radial {
    $pre-spec: nth($gradient-positions, 1);
    $spec:     nth($gradient-positions, 2);
  }

  @if $vendor {
    $vendor-gradients: -#{$vendor}-#{$gradient-type}-gradient(#{$pre-spec} $gradients);
  }
  @else if $vendor == false {
    $vendor-gradients: "#{$gradient-type}-gradient(#{$spec} #{$gradients})";
    $vendor-gradients: unquote($vendor-gradients);
  }
  @return $vendor-gradients;
}

<===> lib/helpers/_shape-size-stripper.scss
@function _shape-size-stripper($shape-size) {
  $shape-size-spec: null;
  @each $value in $shape-size {
    @if ($value == "cover") or ($value == "contain") {
      $value: null;
    }
    $shape-size-spec: "#{$shape-size-spec} #{$value}";
  }
  @return $shape-size-spec;
}

<===> output.css
box:hover {
  -webkit-animation-name: scale, slide;
  -moz-animation-name: scale, slide;
  animation-name: scale, slide;
  -webkit-animation-duration: 2s;
  -moz-animation-duration: 2s;
  animation-duration: 2s;
  -webkit-animation-timing-function: ease;
  -moz-animation-timing-function: ease;
  animation-timing-function: ease;
  -webkit-animation-iteration-count: infinite;
  -moz-animation-iteration-count: infinite;
  animation-iteration-count: infinite;
  -webkit-animation: scale 1s ease-in, slide 2s ease;
  -moz-animation: scale 1s ease-in, slide 2s ease;
  animation: scale 1s ease-in, slide 2s ease;
}

div {
  -webkit-appearance: none;
  -moz-appearance: none;
  -ms-appearance: none;
  -o-appearance: none;
  appearance: none;
  /* boo boo boo */
  background-image: url("/images/a.png"), url("images/b.png");
  background-image: url("/images/a.png"), url("images/b.png");
  background-image: url("/images/a.png"), -webkit-linear-gradient( white 0, yellow 50%, transparent 50%);
  background-image: url("/images/a.png"), linear-gradient( white 0, yellow 50%, transparent 50%);
  background-image: -webkit-linear-gradient( rgba(255, 255, 255, 0.25) 0%, rgba(255, 255, 255, 0.08) 50%, transparent 50%), -webkit-linear-gradient( #4e7ba3, #3e6181);
  background-image: linear-gradient( rgba(255, 255, 255, 0.25) 0%, rgba(255, 255, 255, 0.08) 50%, transparent 50%), linear-gradient( #4e7ba3, #3e6181);
  background-image: -webkit-url("/images/a.png")-gradient( center), -webkit-url("images/b.png")-gradient( left);
  background-image: url("/images/a.png")-gradient( center), url("images/b.png")-gradient( left);
}

<===> output-dart-sass.css
box:hover {
  -webkit-animation-name: scale, slide;
  -moz-animation-name: scale, slide;
  animation-name: scale, slide;
  -webkit-animation-duration: 2s;
  -moz-animation-duration: 2s;
  animation-duration: 2s;
  -webkit-animation-timing-function: ease;
  -moz-animation-timing-function: ease;
  animation-timing-function: ease;
  -webkit-animation-iteration-count: infinite;
  -moz-animation-iteration-count: infinite;
  animation-iteration-count: infinite;
  -webkit-animation: scale 1s ease-in, slide 2s ease;
  -moz-animation: scale 1s ease-in, slide 2s ease;
  animation: scale 1s ease-in, slide 2s ease;
}

div {
  -webkit-appearance: none;
  -moz-appearance: none;
  -ms-appearance: none;
  -o-appearance: none;
  appearance: none;
  /* boo boo boo */
  background-image: url("/images/a.png"), url("images/b.png");
  background-image: url("/images/a.png"), url("images/b.png");
  background-image: url("/images/a.png"), -webkit-linear-gradient(white 0, yellow 50%, transparent 50%);
  background-image: url("/images/a.png"), linear-gradient( white 0, yellow 50%, transparent 50%);
  background-image: -webkit-linear-gradient(rgba(255, 255, 255, 0.25) 0%, rgba(255, 255, 255, 0.08) 50%, transparent 50%), -webkit-linear-gradient(#4e7ba3, #3e6181);
  background-image: linear-gradient( rgba(255, 255, 255, 0.25) 0%, rgba(255, 255, 255, 0.08) 50%, transparent 50%), linear-gradient( #4e7ba3, #3e6181);
  background-image: -webkit-url("/images/a.png")-gradient(center), -webkit-url("images/b.png")-gradient(left);
  background-image: url("/images/a.png")-gradient( center), url("images/b.png")-gradient( left);
}