CSS

Cascading Style Sheets (CSS) is a language used for describing the presentation of a document written ina markup language like HTML. CSS is a cornerstone technology of the World Wide Web, alongside HTML and JavaScript.

CSS is differentiated in to two major categories CSS and CSS3. With the release of CSS3 many more effects and transitions were made possible, eliminating the requirement for expensive libraries such as jQuery needing to be used to get the desired outcome. A negative effect of this however, was that sites utilising newer components would have to pick either working on older browsers via polyfills, or not supporting them at all. This has led to many sites being reluctant to include CSS3 code in the early days.

Usage
In order to start using CSS on a web page, you need to add a style tag. Normally, they are put in the head tag, like so: Inside the style tag, you'll use a different syntax than HTML or JavaScript.

Selectors
You use selectors to select things on the page you want to style. You can select based on Element, Class, or ID, or you can select everything. /* Selecting Everything */ * { } /* Selecting Using Element */ p { } /* Selecting Using ID */ } /* Selecting Using Class */ .class { }
 * 1) uniqueID {

Comments
In the previous example, you saw comments explaining what each selector does. A comment starts with /* and ends with */. They can also span multiple lines.

Declarations
Each declaration block (the part with curly braces) is made up of declarations. A declaration has two parts: a property, and a value, formatted like this: property: value;

Properties
There are various properties in CSS. The table below shows the properties, the values they accept, and what they do.