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

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

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


@mixin small-width {
  @media all and (max-width: 850px) {
    @content;
  }
}

@mixin medium-width {
  @media all and (min-width: 1000px) and (max-width: 1139px) {
    @content;
  }
}

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

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

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

// Clearfix

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

// 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);
}

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

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

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

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

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

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