devroom.io/content/css/zurb-foundation/foundation/components/_dropdown-buttons.scss

//
// Dropdown Button Variables
//

// We use these to set the color of the pip in dropdown buttons
$dropdown-button-pip-color:     #fff !default;
$dropdown-button-pip-color-alt: #333 !default;

// We use these to style tiny dropdown buttons
$dropdown-button-padding-tny:   $button-tny * 5 !default;
$dropdown-button-pip-size-tny:  $button-tny !default;
$dropdown-button-pip-opposite-tny: $button-tny * 2 !default;
$dropdown-button-pip-top-tny:   -$button-tny / 2 + emCalc(1px) !default;

// We use these to style small dropdown buttons
$dropdown-button-padding-sml:   $button-sml * 5 !default;
$dropdown-button-pip-size-sml:  $button-sml !default;
$dropdown-button-pip-opposite-sml: $button-sml * 2 !default;
$dropdown-button-pip-top-sml:   -$button-sml / 2 + emCalc(1px) !default;

// We use these to style medium dropdown buttons
$dropdown-button-padding-med:   $button-med * 4 + emCalc(3px) !default;
$dropdown-button-pip-size-med:  $button-med - emCalc(3px) !default;
$dropdown-button-pip-opposite-med: $button-med * 2 !default;
$dropdown-button-pip-top-med:   -$button-med / 2 + emCalc(2px) !default;

// We use these to style large dropdown buttons
$dropdown-button-padding-lrg:   $button-lrg * 4 !default;
$dropdown-button-pip-size-lrg:  $button-lrg - emCalc(6px) !default;
$dropdown-button-pip-opposite-lrg: $button-lrg + emCalc(12px) !default;
$dropdown-button-pip-top-lrg:   -$button-lrg / 2 + emCalc(3px) !default;

//
// Dropdown Button Mixin
//

// We use this mixin to build off of the button mixin and add dropdown button styles
@mixin dropdown-button($padding:medium, $pip-color:#fff, $base-style:true) {

  // We add in base styles, but they can be negated by setting to 'false'.
  @if $base-style {
    position: relative;

    // This creates the base styles for the triangle pip
    &:before {
      position: absolute;
      content: "";
      width: 0;
      height: 0;
      display: block;
      border-style: solid;
      border-color: $dropdown-button-pip-color transparent transparent transparent;
      top: 50%;
    }
  }

  // If we're dealing with tiny buttons, use these styles
  @if $padding == tiny {
    padding-#{$opposite-direction}: $dropdown-button-padding-tny;
    &:before {
      border-width: $dropdown-button-pip-size-tny;
      #{$opposite-direction}: $dropdown-button-pip-opposite-tny;
      margin-top: $dropdown-button-pip-top-tny;
    }
  }

  // If we're dealing with small buttons, use these styles
  @if $padding == small {
    padding-#{$opposite-direction}: $dropdown-button-padding-sml;
    &:before {
      border-width: $dropdown-button-pip-size-sml;
      #{$opposite-direction}: $dropdown-button-pip-opposite-sml;
      margin-top: $dropdown-button-pip-top-sml;
    }
  }

  // If we're dealing with default (medium) buttons, use these styles
  @if $padding == medium {
    padding-#{$opposite-direction}: $dropdown-button-padding-med;
    &:before {
      border-width: $dropdown-button-pip-size-med;
      #{$opposite-direction}: $dropdown-button-pip-opposite-med;
      margin-top: $dropdown-button-pip-top-med;
    }
  }

  // If we're dealing with large buttons, use these styles
  @if $padding == large {
    padding-#{$opposite-direction}: $dropdown-button-padding-lrg;
    &:before {
      border-width: $dropdown-button-pip-size-lrg;
      #{$opposite-direction}: $dropdown-button-pip-opposite-lrg;
      margin-top: $dropdown-button-pip-top-lrg;
    }
  }

  // We can control the pip color. We didn't use logic in this case, just set it and forget it.
  @if $pip-color {
    &:before { border-color: $pip-color transparent transparent transparent; }
  }
}


@if $include-html-button-classes {

  /* Dropdown Button */
  .dropdown.button { @include dropdown-button;
    &.tiny { @include dropdown-button(tiny,$base-style:false); }
    &.small { @include dropdown-button(small,$base-style:false); }
    &.large { @include dropdown-button(large,$base-style:false); }
    &.secondary:before { border-color: $dropdown-button-pip-color-alt transparent transparent transparent; }
  }

}