<span class="hljs-at_rule">@<span class="hljs-keyword">if</span><span class="hljs-preprocessor"> type-of</span>($base-value) != <span class="hljs-string">"number"</span> {</span>
    <span class="hljs-at_rule">@<span class="hljs-keyword">warn</span> <span class="hljs-string">"base-value: #{$base-value} is not a number"</span>;</span>
    <span class="hljs-at_rule">@return<span class="hljs-preprocessor"> null</span>;</span>
  }
  $value<span class="hljs-value">: _strip-unit($value) / _strip-unit($base-value)