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

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

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

@mixin small-height {
  @media screen and (max-height: 444px) {
    @content;
  }
}

@mixin regular-height {
  @media screen and (min-height: 445px) {
    @content;
  }
}

@mixin not-small-width {
  @media screen and (min-width: 967px) {
    @content;
  }
}

@mixin small-width {
  @media screen and (max-width: 966px) {
    @content;
  }
}

@mixin medium-width {
  @media screen and (min-width: 967px) and (max-width: 1139px) {
    @content;
  }
}

@mixin large-width {
  @media screen and (min-width: 1140px) {
    @content;
  }
}

@mixin mobile-portrait      { @media only screen and (max-width : 320px) { @content; } }
@mixin not-mobile-portrait  { @media only screen and (min-width : 321px) { @content; } }
@mixin mobile-landscape     { @media only screen and (min-width : 321px) and (max-width : 959px) { @content; } }
@mixin not-tablet-landscape { @media only screen and (max-width : 959px) { @content; } }
@mixin tablet-landscape     { @media only screen and (min-width : 960px) { @content; } }

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

// Box sizing

@mixin box-sizing($sizing) {
  -webkit-box-sizing: $sizing;
     -moz-box-sizing: $sizing;
          box-sizing: $sizing;
}

// Border radius

@mixin border-radius-all($radius) {
  border-radius: $radius;
}

// Box shadow

@mixin box-shadow($shadow) {
  box-shadow: $shadow;
}

// Linear gradient

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

// Transition

@mixin transition($transition) {
  .discourse-no-touch & {
    -webkit-transition: #{$transition};
        -ms-transition: #{$transition};
            transition: #{$transition};
  }
}

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

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

@mixin fades-in($time: 0.5s) {
  opacity: 0;
  visibility: hidden;
  .discourse-no-touch & {
    -webkit-transition: visibility 0s linear $time, opacity $time linear;
        -ms-transition: visibility 0s linear $time, opacity $time linear;
            transition: visibility 0s linear $time, opacity $time linear;
  }
}

@mixin visible {
  opacity: 1;
  visibility: visible;
  -webkit-transition-delay: 0s;
          transition-delay: 0s;
}

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

// Unselectable

@mixin unselectable {
  -webkit-user-select: none;
     -moz-user-select: none;
      -ms-user-select: none;
}