locale.css 

.locale-untranslated {
  font-style: normal;
  text-decoration: line-through;
}

Archivo

drupal-6.x/modules/locale/locale.css
View source 
  1. 

  2. .locale-untranslated {

  3.   font-style: normal;

  4.   text-decoration: line-through;

  5. }