title: Connected styles in Scene Builder is not found in runtime
body: <p>I create <code>Pane</code> in Scene Builder for Java 8. My <code>.css</code> files store in <code>/rescouces/css/app.css</code>. I connect stylesheet in <code>Scene Builder</code> and all ok. But after i start my app i get exception with error:
  <code>Caused by: javafx.fxml.LoadException: Invalid resource: /../style/app.css not found on the classpath</code>.</p>
  
  <p>How to fix this? I need every time rename path to <code>css</code> in <code>.fxml</code>?</p>
  
  <p><a href="https://i.stack.imgur.com/EKcSJ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/EKcSJ.png" alt="enter image description here"></a></p>
  
  <pre><code>&lt;AnchorPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="912.0" prefWidth="1368.0" styleClass="app" stylesheets="@/style/app.css" xmlns="http://javafx.com/javafx/8.0.172-ea" xmlns:fx="http://javafx.com/fxml/1" fx:controller="com.mypod.tablet.controller.MainController"&gt;
      &lt;children&gt;
          &lt;AnchorPane fx:id="contentPane" layoutX="248.0" layoutY="138.0" stylesheets="@/style/content.css" AnchorPane.bottomAnchor="94.0" AnchorPane.leftAnchor="250.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="115.0"&gt;
              &lt;styleClass&gt;
                  &lt;String fx:value="block" /&gt;
                  &lt;String fx:value="content-block" /&gt;
              &lt;/styleClass&gt;
          &lt;/AnchorPane&gt;
      &lt;/children&gt;
  &lt;/AnchorPane&gt;
  </code></pre>
  
  <p>Load fxml:</p>
  
  <pre><code>FXMLLoader loader = new FXMLLoader();
  
  this.primaryStage.setScene(new Scene(loader.load(Util.getResource("/fxml/main.fxml"))));
  </code></pre>