public function align($direction = 'horizontal', $collapse = 'sm', $indent = 2)
    {
        if ($direction == 'collapse') {
            $this->align = '';
        } elseif ($direction == 'inline') {
            $this->align = 'form-inline';
        } else {
            $this->align = 'form-horizontal';
            $this->collapse = (in_array($collapse, array('xs', 'sm', 'md', 'lg'))) ? $collapse : 'sm';
            $this->indent = (is_numeric($indent) && $indent > 0 && $indent < 12) ? $indent : 2;
        }
    }