discourse/app/assets/stylesheets/common/foundation/mixins.scss

// --------------------------------------------------
// Mixins used throughout the theme
// --------------------------------------------------

// Media queries
// --------------------------------------------------

$breakpoints: (
  mobile-small: 320px,
  mobile-medium: 350px,
  mobile-large: 450px,
  mobile-extra-large: 550px,
  tablet: 768px,
  medium: 850px,
  large: 1000px,
  extra-large: 1140px
);

@mixin breakpoint($bp, $rule: max-width, $type: screen) {
  @media #{$type} and (#{$rule}: map-get($breakpoints, $bp)) {
    @content;
  }
}

// CSS3 properties
// --------------------------------------------------

// Clearfix

@mixin clearfix() {
  &:before,
  &:after {
    content: "";
    display: table;
  }
  &:after {
    clear: both;
  }
}

//noinspection CssOptimizeSimilarProperties
@mixin linear-gradient($start-color, $end-color) {
  background-color: $start-color;
  background-image: linear-gradient(to bottom, $start-color, $end-color);
}

// Visibility
// --------------------------------------------------

@mixin hover {
  .discourse-no-touch & {
    &:hover {
      @content;
    }
  }
}

//
// --------------------------------------------------

// Unselectable (avoids unwanted selections with iPad, touch laptops, etc)

@mixin user-select($mode) {
  -webkit-user-select: $mode;
  -moz-user-select: $mode;
  -ms-user-select: $mode;
}

@mixin unselectable {
  @include user-select(none);
}

// Stuff we repeat
@mixin post-aside {
  border-left: 5px solid $primary-low;
  background-color: blend-primary-secondary(5%);
}

// We still need -webkit for latest iPhone and Safari
@mixin transform($transforms) {
  -webkit-transform: $transforms;
  transform: $transforms;
}

@mixin appearance-none() {
  // resets default browser styles
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
}

@mixin fa-rotate($degrees, $rotation) {
  -ms-filter: "progid:DXImageTransform.Microsoft.BasicImage(rotation=#{$rotation})";
  -webkit-transform: rotate($degrees);
  -ms-transform: rotate($degrees);
  transform: rotate($degrees);
}

/// Helper function to easily use an SVG inline in CSS
/// without encoding it to base64, saving bytes.
/// It also helps with browser support, especially for IE11.
///
/// @author Jakob Eriksen
/// @link http://codepen.io/jakob-e/pen/doMoML
/// @param {String} $svg - SVG image to encode
/// @return {String} - Encoded SVG data uri
@function svg-uri($svg) {
  $encoded: "";
  $slice: 2000;
  $index: 0;
  $loops: ceil(str-length($svg) / $slice);

  @for $i from 1 through $loops {
    $chunk: str-slice($svg, $index, $index + $slice - 1);
    $chunk: str-replace($chunk, '"', "'");
    $chunk: str-replace($chunk, "<", "%3C");
    $chunk: str-replace($chunk, ">", "%3E");
    $chunk: str-replace($chunk, "&", "%26");
    $chunk: str-replace($chunk, "#", "%23");
    $encoded: #{$encoded}#{$chunk};
    $index: $index + $slice;
  }

  @return url("data:image/svg+xml;charset=utf8,#{$encoded}");
}

/// Replace `$search` with `$replace` in `$string`
/// @author Hugo Giraudel
/// @link http://sassmeister.com/gist/1b4f2da5527830088e4d
/// @param {String} $string - Initial string
/// @param {String} $search - Substring to replace
/// @param {String} $replace ('') - New value
/// @return {String} - Updated string
@function str-replace($string, $search, $replace: "") {
  $index: str-index($string, $search);

  @if $index {
    @return str-slice($string, 1, $index - 1) + $replace +
      str-replace(
        str-slice($string, $index + str-length($search)),
        $search,
        $replace
      );
  }

  @return $string;
}