If you don’t know what CSS at all, or how it is used but would like to get a basic familiarity with it, this guide is for you. CSS stands for Cascading Style Sheets. Simply, it is a way for web designers to easily define how your site will look.
To understand what CSS is, you should first understand why it was developed in the first place. Before CSS was invented, both the content & text for every website, and it’s style were all included in one document. This meant that if you wanted to change a color across your entire site you would have to go into every single web page on the site and make the changes to each.