class='highlight'><pre><span class="hljs-at_rule">@<span class="hljs-keyword">mixin</span><span class="hljs-preprocessor"> col-container</span> {</span>
  $valid<span class="hljs-value">: true;</span>
  <span class="hljs-at_rule">@<span class="hljs-keyword">if</span><span class="hljs-preprocessor"> type-of</span>($grid-max-width) != <span class="hljs-string">"number"</span> {</span>
    <span class="hljs-at_rule">@<span class="hljs-keyword">warn</span> <span class="hljs-string">"grid-max-width: #{$grid-max-