title: Styling prompt text separately from text in JFXTextField
body: <p>I am using JFoenix library elements. I have a simple login interface. 
  I use JFXTextfields with a LabelFloat option. When the text field is empty the prompt text weight is normal. But when the text field is unfocused and non-empty I need the text weight to be changed to be bold and its size increased, I also need the label Float to stay with <code>th</code> initial font size and a normal weight.</p>
  
  <p>This is my css:</p>
  
  <pre><code>.input-field-blue {
      -fx-prompt-text-fill: #a1a1a1;
      -jfx-unfocus-color : #bcbcbc;
      -fx-background-repeat : no-repeat;
      -fx-background-position: right center;
      -fx-padding : 0 -8 4 0;
      -fx-text-fill : #3fc9ee;
  }
  .input-field-blue:filled {
      -fx-font-size: 14;
      -fx-font-weight: bold;
      -fx-text-fill : #00adde;
      -jfx-unfocus-color : #00adde;
  }
  </code></pre>
  
  <p>This is my fxml file:</p>
  
  <pre><code>&lt;AnchorPane fx:id="backPanel" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity"
              prefHeight="675.0" prefWidth="1200.0" stylesheets="@../sample/sylesheet.css"
              xmlns="http://javafx.com/javafx/8.0.171" xmlns:fx="http://javafx.com/fxml/1" fx:controller="View.LoginView"&gt;
      &lt;children&gt;
          &lt;Pane fx:id="frontPanel" layoutX="396.0" layoutY="164.0" prefHeight="351.0" prefWidth="450.0"
                style="-fx-background-color: #ffffff;" styleClass="front-panel"&gt;
              &lt;children&gt;
                  &lt;Label fx:id="hiLabel" layoutX="166.0" layoutY="43.0" styleClass="title-blue" text="Bonjour !"
                         textAlignment="CENTER"/&gt;
                  &lt;Label fx:id="highlightLabel" layoutX="115.0" layoutY="99.0" styleClass="highlight"
                         text="Veuillez vous authentifier s’il vous plaît"/&gt;
                  &lt;JFXPasswordField fx:id="pwd" focusColor="#3fc9ee" labelFloat="true" layoutX="77.0" layoutY="207.0"
                                    prefHeight="26.0" prefWidth="297.0" promptText="Mot de passe" unFocusColor="#bcbcbc"&gt;
                      &lt;styleClass&gt;
                          &lt;String fx:value="input-field-blue"/&gt;
                      &lt;/styleClass&gt;
                  &lt;/JFXPasswordField&gt;
                  &lt;JFXButton fx:id="authButton" layoutX="155.0" layoutY="277.0" prefHeight="38.0" prefWidth="140.0"
                             styleClass="button-blue" text="S'authentifier" textAlignment="CENTER"/&gt;
                  &lt;JFXTextField fx:id="userName" focusColor="#3fc9ee" labelFloat="true" layoutX="76.0" layoutY="147.0"
                                prefHeight="26.0" prefWidth="297.0" promptText="Nom d'utilisateur" unFocusColor="#bcbcbc"&gt;
                      &lt;styleClass&gt;
                          &lt;String fx:value="input-field-blue"/&gt;
                      &lt;/styleClass&gt;
                  &lt;/JFXTextField&gt;
              &lt;/children&gt;
          &lt;/Pane&gt;
      &lt;/children&gt;
      &lt;styleClass&gt;
          &lt;String fx:value="back-panel"/&gt;
          &lt;String fx:value="back-panel-blue"/&gt;
      &lt;/styleClass&gt;
  &lt;/AnchorPane&gt;
  </code></pre>
  
  <p>I have this interface:</p>
  
  <p><a href="https://i.stack.imgur.com/qWxeH.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/qWxeH.png" alt="Label Float has a bold weight"></a></p>
  
  <p>But what I want:</p>
  
  <p><a href="https://i.stack.imgur.com/LpABP.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/LpABP.png" alt="Label Float should have a normal font weight"></a></p>
  
  <p>Is there anyway to do that ?</p>