How to remove Java FX Accordion default borders?

I have simple form which has Accordion container with 2 elements.
I want to remove or modify the Accordion default borders.

My FXMLDocument.fxml file:

<AnchorPane id="AnchorPane" prefHeight="400.0" prefWidth="600.0" styleClass="form" stylesheets="@styles.css" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/10.0.1">
    <children>
      <Accordion layoutX="100.0" layoutY="75.0" prefHeight="250.0" prefWidth="400.0">
        <panes>
          <TitledPane styleClass="acc-titled-pane" text="Option 1">
            <content>
                <AnchorPane prefHeight="180.0" prefWidth="200.0" styleClass="acc-pane-body">
                </AnchorPane>
            </content>
          </TitledPane>
          <TitledPane styleClass="acc-titled-pane" text="Option 2">
            <content>
                <AnchorPane prefHeight="180.0" prefWidth="200.0" styleClass="acc-pane-body">
                </AnchorPane>
            </content>
          </TitledPane>
        </panes>
      </Accordion>
    </children>
</AnchorPane>

My styles.css file:

.form {
    -fx-background-color: lightgreen;
}
.acc-titled-pane {
    -fx-border-color: transparent;
}
.acc-pane-body {
    -fx-background-color: lightgreen;
    -fx-border-color: transparent;
}

As you can see, I made all borders transparent, but there are still some borders: I have tried a lot of css rules, but none of them worked for me.

First of all You should style the .content subclass of TitledPane (docs).

Additionally you should set -fx-border-width instead of -fx-border-color because even transparent will result in the parents background shining through:

If you set the border width of the content subclass to 0 it should solve your problem:

.acc-titled-pane .content {
    -fx-border-width: 0;
}

The result will be: