Prestashop language detection sentence

<!-- Made by Eimantas Kasperiūnas - http://kasperiunas.com -->
 <!-- if language is equal to EN add this -->
 {if $lang_iso == en}{include file=$tpl_dir./path-to-css-file.css}{/if}
  <!-- if language is equal to DE add this -->
 {if $lang_iso == de}{include file=$tpl_dir./path-to-css-file.css}{/if}
  <!-- if language is equal to ES add this -->
 {if $lang_iso == es}{include file=$tpl_dir./path-to-css-file.css}{/if}