@Luis the default Casper theme does not use translation helpers, if you want to use the WorldCasper2 es.json locale file you’ll need to use it with the WordCasper2 theme.
But I understand that if I use that repo I won’t be enjoying great things like the dark mode. I could try to translate the 3.0, but having to work each time you update the theme is far from great.
I understand that this is your native language, but please, support localization so non-tech people can enjoy it.