Here is peace of code that can allow you to link CSS per controller action, just place the code in to the layout head section /app/views/layouts/default.ctp:
// view specific CSS - css// $action = $this->params["controller"] != 'pages' ? $this->params["action"] : $this->params["pass"]['0']; if (is_file(APP.WEBROOT_DIR.DS."css".DS.$this->params["controller"].DS.$action.".css")) { echo $html->css($this->params["controller"]."/".$action); }.css or /css/pahes/ .css linking, if CSS file exists