In the past there was a plugin "css4k2" to load a css file from an override template.
It seems that it not anymore available.
Unfortunately, the video that explain the override process is old and I did not find a simple solution like it.
Could you pls let me know how to load automatically a css file tied with an override template?
Many thanks for your help

Try putting a copy of k2.css in your templates/YOURTEMPLATE/css/ directory , make changes and they should load
Also, check your templates "custom.css" file. Many tmeplates allow you to use this file to override any css on the site by adding what you want there

I do not think it works, because I need a different css file for each override template.
the plugin was fantastic /as shown in the video class). Just naming the css file equal to the override template, assign to a page the template to use and the plugin loaded the correct css file.

It won't work this way. The CSS file is a global one, since you can add your own classes in your overrides there is no need to add multiple stylesheets. You can also add custom stylesheets using Joomla!'s API in your template.

Im sorry but using K2 you van have different templates and assign them to the pages you like, so you can have different css file one for each templarìte and you can modify the K2 classes.
plase watch this video: www.youtube.com/watch?v=vprpuc5pLHI
ciao

Yes but still these stylesheets have to be added manually without css4K2.