{$device} ) ) { if ( !empty( $this->{$device}->enable ) ) { $duration = isset( $this->{$device}->duration ) ? $this->{$device}->duration : 0; $css[ $device ][ self::NAME ] = "all " . $this->{$device}->timingFunction . ' ' . $duration . 's'; } } } return $css; } }