CSS is for styling or positioning content. It is not used to create or edit translations or any other content.
Here are the steps to translate “Read More” into your language.
In your dashboard go to ‘Loco Translate’ > ‘Themes’
Click on ‘Trusted Pro’
Click on ‘New Language’
Choose your language in ‘WordPress language’
Click ‘Start translating’ button
Scroll through ‘Source text’ until you find ‘Read More’
Write your own translation of Read More in the translation box and click ‘Save’ button, see attached image
That’s it. Now the blog post excerpts will show the translated text instead of read more.