What is CSS File and why it is used?

A CSS file can tell the web browser how a web page is supposed to look. The web page (HTML file) itself says what Words are on the page, and which pictures, but you CAN use the CSS file to specify what goes where, how big, what color and font, and things like that.

You CAN also specify all those things in the HTML file. The biggest advantages of using separate CSS are:

1. The same CSS file can be used for all pages in a site, so if you want to change something, you can just change it in one place, and all the pages will now look the way you want.
2. If you use the same CSS file for every page, your pages will load faster, since the browser does not re-fetch the CSS file every time.