Cascading Style Sheets or (CSS) works alongside Hypertext Markup Language (HTML). HTML is the code that tells a browser how to display a web page. Previously in HTML you had to code every row to describe the fonts, backgrounds, positioning etc.
CSS allows you to to state how the layout of the site will look, ensure uniformity across different pages, and it allows your web page to download quicker, helping to make sure that your potential new customers don’t get bored and go find someone else’s site.
CSS code can be on either a separate document, written in the header of the HTML web page, or even written inline with the HTML code. depending on what you need that bit of code to affect.
At it’s most basic you can code CSS to make all your text written in H1 the largest title tag across your site to be written in red, bold and in Arial.
CSS code can be used to arrange the layout of the page. It can create areas on the page for the text to be displayed in columns or blocks, or it can be used to position and stack images.
Linking your regular HTML pages to a separate CSS document makes it easy to change presentation, layout and general appearance of all linked pages very quickly. You need only to make the changes on the one document, not every page on the site.
Do I need it? Well it depends on you and how user friendly you want your site to be behind the scenes. It is still possible to code a site purely in HTML, but this takes a lot longer as you can imagine having to describe how every line of text looks. CSS reduces the initial time it takes to code the the site but also makes re-designing sites or making changes to the whole site a lot quicker and more efficient. Most sites these days will be designed using CSS and HTML, but if you’re getting someone else to create your site, it is always worth checking.