I'm correcting the question. I've checked the modified files now and the values ​​are the ones I entered when I modified them, but I can't see them in the front end of the site. Why?

Ciao,

you forgot to read Helix documenation - that's why. People still make the same mistake, over and over.

Whole info is here: https://www.joomshaper.com/documentation/helix-framework/custom-code-css-js-meta#documentation-heading-3 (just read, also red box)

I can help more you only if you used Custom CSS field or custom.css file.

OK. Anyway, it's strange because I've used your templates, including the one in question, and I've always made the changes directly in the files, not in the custom.css, and they've never given me these problems. Why am I having this problem this time? Really strange.

Editing template core file(s) is never a good idea.

Just use custom.css file for changes as we teach in manual.

and what if I need to modify the preset1 css file?

What would happen if you update template in next weeks/months that will override that file anyway. think!!! you have answer already.

ok I understood this and that is that I can modify the template.css file via custom.css file, but I would like to know what I should do to modify the preset1.css file I also wanted to ask you to better understand why when I open the template.css file I see the changes I made but I don't see them on the site's front end. Which file does the site read that saw that the changes I made in the template.css file are there? thank you

check on front-end order of loading .css files, when custom.css is loaded, after or before presets and template.css