My CSS doesn't refresh when linked to my HTML



I have the following CSS code:
CSS code screenshot
which is linked to some html files by doing this:
HTML code screenshot
and this is my project route:

I have been reading many threads about the problems people have had when linking their css to the html, my case is a bit weird and different. If I use the html style tag and I write the css code inside there, it works perfectly. However, for comfort purposes, I’d like to use the linking method but when I do this, if I change anything in the css file it doesn’t change, it’s like it doesn’t refresh itself. Any help would be greatly appreciated, many thanks.