public function getCustomCSS()
    {
        // Create CSS Array:
        
        $css = [];
        
        // Merge Custom CSS from Template:
        
        foreach (ClassTools::singleton()->getObjectAncestry($this, self::class) as $class) {
            
            $template = $this->getCustomCSSTemplate($class);
            
            if (SSViewer::hasTemplate($template)) {
                $css = ViewTools::singleton()->renderCSS($this, $template, $css);
            }
            
        }
        
        // Update CSS via Extensions:
        
        $this->extend('updateCustomCSS', $css);
        
        // Filter CSS Array:
        
        $css = array_filter($css);
        
        // Answer CSS Array:
        
        return $css;
    }