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

//
// Split Button Variables
//

// We use these to control different shared styles for Split Buttons
$split-button-function-factor: 15% !default;
$split-button-pip-color:       #fff !default;
$split-button-pip-color-alt:   #333 !default;
$split-button-active-bg-tint:  rgba(0,0,0,0.1) !default;

// We use these to control tiny split buttons
$split-button-padding-tny:     $button-tny * 9 !default;
$split-button-span-width-tny:  $button-tny * 6.5 !default;
$split-button-pip-size-tny:    $button-tny !default;
$split-button-pip-top-tny:     $button-tny * 2 !default;
$split-button-pip-default-float-tny:    emCalc(-5px) !default;

// We use these to control small split buttons
$split-button-padding-sml:     $button-sml * 7 !default;
$split-button-span-width-sml:  $button-sml * 5 !default;
$split-button-pip-size-sml:    $button-sml !default;
$split-button-pip-top-sml:     $button-sml * 1.5 !default;
$split-button-pip-default-float-sml:    emCalc(-9px) !default;

// We use these to control medium split buttons
$split-button-padding-med:     $button-med * 6.4 !default;
$split-button-span-width-med:  $button-med * 4 !default;
$split-button-pip-size-med:    $button-med - emCalc(3px) !default;
$split-button-pip-top-med:     $button-med * 1.5 !default;
$split-button-pip-default-float-med:    emCalc(-9px) !default;

// We use these to control large split buttons
$split-button-padding-lrg:     $button-lrg * 6 !default;
$split-button-span-width-lrg:  $button-lrg * 3.75 !default;
$split-button-pip-size-lrg:    $button-lrg - emCalc(6px) !default;
$split-button-pip-top-lrg:     $button-lrg + emCalc(5px) !default;
$split-button-pip-default-float-lrg:    emCalc(-9px) !default;


//
// Split Button Mixin
//

// We use this mixin to create split buttons that build upon the button mixins
@mixin split-button($padding:medium, $pip-color:$split-button-pip-color, $span-border:$primary-color, $base-style:true) {

  // With this, we can control whether or not the base styles come through.
  @if $base-style {
    position: relative;

    // Styling for the split arrow clickable area
    span {
      display: block;
      height: 100%;
      position: absolute;
      #{$opposite-direction}: 0;
      top: 0;
      border-#{$default-float}: solid 1px;

      // Building the triangle pip indicator
      &:before {
        position: absolute;
        content: "";
        width: 0;
        height: 0;
        display: block;
        border-style: solid;

        #{$default-float}: 50%;
      }

      &:active { background-color: $split-button-active-bg-tint; }
    }
  }

  // Control the border color for the span area of the split button
  @if $span-border {
    span { border-#{$default-float}-color: darken($span-border, $split-button-function-factor); }
  }

  // Style of the button and clickable area for tiny sizes
  @if $padding == tiny {
    padding-#{$opposite-direction}: $split-button-padding-tny;

    span { width: $split-button-span-width-tny;
      &:before {
        border-width: $split-button-pip-size-tny;
        top: $split-button-pip-top-tny;
        margin-#{$default-float}: $split-button-pip-default-float-tny;
      }
    }
  }

  // Style of the button and clickable area for small sizes
  @else if $padding == small {
    padding-#{$opposite-direction}: $split-button-padding-sml;

    span { width: $split-button-span-width-sml;
      &:before {
        border-width: $split-button-pip-size-sml;
        top: $split-button-pip-top-sml;
        margin-#{$default-float}: $split-button-pip-default-float-sml;
      }
    }
  }

  // Style of the button and clickable area for default (medium) sizes
  @else if $padding == medium {
    padding-#{$opposite-direction}: $split-button-padding-med;

    span { width: $split-button-span-width-med;
      &:before {
        border-width: $split-button-pip-size-med;
        top: $split-button-pip-top-med;
        margin-#{$default-float}: $split-button-pip-default-float-med;
      }
    }
  }

  // Style of the button and clickable area for large sizes
  @else if $padding == large {
    padding-#{$opposite-direction}: $split-button-padding-lrg;

    span { width: $split-button-span-width-lrg;
      &:before {
        border-width: $split-button-pip-size-lrg;
        top: $split-button-pip-top-lrg;
        margin-#{$default-float}: $split-button-pip-default-float-lrg;
      }
    }
  }

  // Control the color of the triangle pip
  @if $pip-color {
    span:before { border-color: $pip-color transparent transparent transparent; }
  }
}


@if $include-html-button-classes {

  /* Split Buttons */
  .split.button { @include split-button;

    &.secondary { @include split-button(false, $split-button-pip-color, $secondary-color, false); }
    &.alert { @include split-button(false, false, $alert-color, false); }
    &.success { @include split-button(false, false, $success-color, false); }

    &.tiny { @include split-button(tiny, false, false, false); }
    &.small { @include split-button(small, false, false, false); }
    &.large { @include split-button(large, false, false, false); }

    &.secondary { @include split-button(false, $split-button-pip-color-alt, false, false); }

    &.radius span { @include side-radius($opposite-direction, $global-radius); }
    &.round span { @include side-radius($opposite-direction, 1000px); }
  }

}