private void adjustTextColors() {
        Color brightColor = getBrightTextColor();
        Color darkColor   = getDarkTextColor();
        root.stream().forEach(node -> {
            ChartData data = node.getItem();
            boolean darkFillColor = Helper.isDark(data.getFillColor());
            boolean darkTextColor = Helper.isDark(data.getTextColor());
            if (darkFillColor && darkTextColor) { data.setTextColor(brightColor); }
            if (!darkFillColor && !darkTextColor) { data.setTextColor(darkColor); }
        });
    }
Defines the root element of the tree
@param TREE
src/main/java/eu/hansolo/tilesfx/chart/SunburstChart.java