=vex-keyframes($name)
    @keyframes #{$name}
        @content
    @-webkit-keyframes #{$name}
        @content
    @-moz-keyframes #{$name}
        @content
    @-ms-keyframes #{$name}
        @content
    @-o-keyframes #{$name}
        @content

=vex-animation($animation)
    animation: $animation
    -webkit-animation: $animation
    -moz-animation: $animation
    -ms-animation: $animation
    -o-animation: $animation
    -webkit-backface-visibility: hidden

=vex-transform($transform)
    transform: $transform
    -webkit-transform: $transform
    -moz-transform: $transform
    -ms-transform: $transform
    -o-transform: $transform

=vex-preserve-3d
    -webkit-transform-style: preserve-3d
    -moz-transform-style: preserve-3d
    transform-style: preserve-3d

// copied from Compass (https://github.com/Compass/compass) on the 21st of January 2015:

$prefix-context: null
$current-prefix: null
$critical-usage-threshold: 0.01 !default
$default-has-layout-approach: zoom !default
$has-layout-support-threshold: $critical-usage-threshold !default

// full mixin: https://github.com/Compass/compass/blob/stable/core/stylesheets/compass/_support.scss
=box-sizing($box-model)
    -moz-box-sizing: $box-model
    -webkit-box-sizing: $box-model
    box-sizing: $box-model

// full mixin: https://github.com/Compass/compass/blob/stable/core/stylesheets/compass/css3/_box-shadow.scss
=box-shadow($shadow...)
    -moz-box-shadow: $shadow
    -webkit-box-shadow: $shadow
    box-shadow: $shadow

// full mixin: https://github.com/Compass/compass/blob/stable/core/stylesheets/compass/css3/_border-radius.scss
=border-radius($radius)
    -moz-border-radius: $radius
    -webkit-border-radius: $radius
    border-radius: $radius

// full mixin: https://github.com/Compass/compass/blob/stable/core/stylesheets/compass/css3/_transform.scss
=perspective($p)
    -moz-perspective: $p
    -webkit-perspective: $p
    perspective: $p

// full mixin: https://github.com/Compass/compass/blob/stable/core/stylesheets/compass/css3/_transform.scss
=perspective-origin($origin: 50%)
    -moz-perspective-origin: $origin
    -webkit-perspective-origin: $origin
    perspective-origin: $origin

// full mixin: https://github.com/Compass/compass/blob/stable/core/stylesheets/compass/_support.scss
=appearance($appearance)
    $appearance: unquote($appearance)
    -moz-appearance: $appearance
    -webkit-appearance: $appearance

=has-layout($approach: $default-has-layout-approach)
    @if support-legacy-browser("ie", "7", $threshold: $has-layout-support-threshold)
        @if $approach == zoom
            +has-layout-zoom
        @else if $approach == block
            +has-layout-block
        @else
            @warn "Unknown has-layout approach: #{$approach}"
            +has-layout-zoom

=has-layout-zoom
    @if support-legacy-browser("ie", "7", $threshold: $has-layout-support-threshold)
        *zoom: 1

=pie-clearfix
    &:after
        content: ""
        display: table
        clear: both
    +has-layout

// full mixin: https://github.com/Compass/compass/blob/stable/core/stylesheets/compass/_support.scss
@function support-legacy-browser($browser, $min-version, $max-version: null, $threshold: $critical-usage-threshold)
    @return true