What is CSS?

CSS (Cascading Style Sheets) is a language used to specify the layout, formatting, and styles in HTML documents.  That explains all but the cascading part – cascading means that you can override styles for different parts of the HTML page at several levels (that cascade).  For example, let’s say you want all your paragraphs to be colored blue on your entire website.  You can create a CSS file that does that for your whole site (you reference that one file in all your HTML files).  One day, you decide to create a page where you’d rather have your paragraphs be colored red instead of blue.  In that one page, you can use CSS to override the blue paragraph style and make it red.

One core purpose of CSS is to decouple the style of your web content (CSS) from the actual content (HTML).  This way, you can alter how your pages appear without having to work around the actual content, putting it as risk of inadvertent change.

There are multiple versions of CSS, meaning there are multiple version standards for how CSS should behave when interpreted by a web browser.  Sometimes, web browsers don’t follow the standards to the letter which can lead to inconsistencies in web page behavior between different browsers or different versions of the same browser.  All of this has to be worked out through testing.

If you have questions about CSS or about how we use it, contact us.