Just wondering how/why this works, when I'm making a simple html file and linking in some css, then dragging my html file into the browser, no static web server is needed for me to view the file. 

Why is that so..

I'm looking at my browser's network tab, and no request is made for the css file, and my browser still displays it perfectly..

Is there a way to do without a static file server on the web for html, css, js files, like when dragging and dropping a file into a browser?

Just going back and requestionning basics here..

Thanks in advance!