title: LESS - Assign mixin to variable and reuse
body: <p>Given this LESS mixin:</p>
  
  <pre><code>#gradient {
    .vertical (@startColor: #555, @endColor: #333) {
        background-color: @endColor;
        background-repeat: repeat-x;
        background-image: -khtml-gradient(linear, left top, left bottom, from(@startColor), to(@endColor)); /* Konqueror */
        background-image: -moz-linear-gradient(@startColor, @endColor); /* FF 3.6+ */
        background-image: -ms-linear-gradient(@startColor, @endColor); /* IE10 */
        background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0%, @startColor), color-stop(100%, @endColor)); /* Safari 4+, Chrome 2+ */
        background-image: -webkit-linear-gradient(@startColor, @endColor); /* Safari 5.1+, Chrome 10+ */
        background-image: -o-linear-gradient(@startColor, @endColor); /* Opera 11.10 */
        filter: e(%("progid:DXImageTransform.Microsoft.gradient(startColorstr='%d', endColorstr='%d', GradientType=0)",@startColor,@endColor)); /* IE6 &amp; IE7 */
        -ms-filter: %("progid:DXImageTransform.Microsoft.gradient(startColorstr='%d', endColorstr='%d', GradientType=0)",@startColor,@endColor); /* IE8+ */
        background-image: linear-gradient(@startColor, @endColor); /* the standard */
    }
  }
  </code></pre>
  
  <p>It would normally be called as follows to style the header/footer:</p>
  
  <pre><code>header {
      #gradient &gt; .vertical(@black, @white);
      width: 100%;
  }
  
  footer {
      #gradient &gt; .vertical(@black, @white);
      padding: 20px;
  }
  </code></pre>
  
  <p>That works no problem. However, I am trying to assign the <code>#gradient &gt; .vertical(@black, @white);</code> to a variable <code>gradient1</code> and re-use it. So something like this ideally:</p>
  
  <pre><code>@gradient1:      #gradient &gt; .vertical(@black, @white);
  @headerBackground:    @gradient1;
  @footerBackground:    @gradient1;    
  header { @headerBackground; width: 100%; }
  footer { @footerBackground; padding: 20px; }
  </code></pre>
  
  <p>This does not work - but how can this be fixed to work?</p>