title: Apply CSS style to flash message
body: <p>My app is based on Sinatra.  I am using the sinatra-flash gem to generate flash messages if the user does not select enough items to compare.  This aspect of things works, but I cannot seem to apply the style I want to the messages.  Here is my css:</p>
  
  <pre><code>.warning {
        background-color: #f89406;
        border-color: #e96506;
        color: #ffffff;
      }
  </code></pre>
  
  <p>and the code from the view:</p>
  
  <pre><code>&lt;% if flash[:warning] %&gt;
    &lt;div class="warning"&gt;&lt;%= flash[:warning] %&gt;&lt;/div&gt;
  &lt;% end %&gt;
  </code></pre>