How to use a CSS stylesheet file uploaded on the web in a local project?

I'm working on a HTML-CSS project. I found a CSS file on the web but, there was not anyway to download the file. I just know how to use a CSS file in my local project, not a file on the web. How can I use this file on the web in my project?

please answer my question in a couple of code with a example URL. For Example : http://example.com

Thanks.