public function getCustomCSSAsString()
    {
        // Create CSS Array:
        
        $css = [];
        
        // Merge Custom CSS from Page Controller:
        
        if ($this->owner instanceof PageController) {
            $css = array_merge($css, $this->owner->getCustomCSS());
        }
        
        // Create CSS String:
        
        $css = implode("\n", $css);
        
        // Remove Empty Lines:
        
        $css = ViewTools::singleton()->removeEmptyLines($css);
        
        // Trim CSS String:
        
        $css = trim($css);
        
        // Minify CSS String:
        
        if (!Director::isDev()) {
            $css = ViewTools::singleton()->minifyCSS($css);
        }
        
        // Answer CSS String:
        
        return $css;
    }