roundcubemail/program/lib/Roundcube/rcube_plugin_api.php
public function include_stylesheet($fn)
    {
        if (is_object($this->output) && $this->output->type == 'html') {
            $src = $this->resource_url($fn);
            $this->output->include_css($src);
        }
    }
public function include_stylesheet($fn)
    {
        if (is_object($this->output) && $this->output->type == 'html') {
            $src = $this->resource_url($fn);
            $this->output->include_css($src);
        }
    }
public function include_stylesheet ( $ fn ) { if ( is_object ( $ this -> output ) && $ this -> output -> type == 'html' ) { $ src = $ this -> resource_url ( $ fn ) ; $ this -> output -> include_css ( $ src ) ; } }
Include a plugin stylesheet in the current HTML page

@param string $fn Path to stylesheet
Include a plugin stylesheet in the current HTML page