@Override
  public void registerReferenceProviders(@NotNull PsiReferenceRegistrar registrar) {
    registrar.registerReferenceProvider(FXML_PATTERN, new JavaFxFileReferenceProvider(JavaFxFileTypeFactory.FXML_EXTENSION));
    registrar.registerReferenceProvider(STYLESHEET_PATTERN, new JavaFxFileReferenceProvider("css") {
      @Override
      protected String preprocessValue(String value) {
        if (value.endsWith(".bss")) {
          return StringUtil.trimEnd(value, ".bss") + ".css";
        }
        return value;
      }
    });
  }
@Override
  public void registerReferenceProviders(@NotNull PsiReferenceRegistrar registrar)