title: Error: no mixin named transition with Susy in Woocommerce
body: <p>I'm compiling Woocommerce's Storefront theme using Gulp and Sass and came across an error with one of the mixins:</p>
  
  <p>Error in plugin "sass"
  Message:
      storefront/assets/css/woocommerce/woocommerce.scss
  Error: no mixin named transition
          on line 2831 of storefront/assets/css/woocommerce/woocommerce.scss, in mixin <code>@content</code>
          from line 52 of node_modules/susy/sass/susy/language/susy/_breakpoint-plugin.scss, in mixin <code>susy-media</code>
          from line 1881 of storefront/assets/css/woocommerce/woocommerce.scss</p>
  
  <blockquote>
    <blockquote>
  <pre><code>                         @include transition( left 0.3s ease-out );
  </code></pre>
    </blockquote>
  </blockquote>
  
  <p>Any ideas? </p>
  
  <p>PS. There were some other problems with the Susy but downgrading to the susy-2.2.14 solve them. </p>
  
  <hr>
  
  <p><strong>EDIT:</strong> Solved by adding: </p>
  
  <pre><code>@mixin transition($args...) { 
      -webkit-transition: $args; 
      -moz-transition: $args; 
      -ms-transition: $args; 
      -o-transition: $args; 
      transition: $args; 
  } 
  </code></pre>