CSS, or Cascading Style Sheets, is a style sheet language developed to control the presentation of markup language documents like HTML. You can think of HTML as controlling the structure of the web, while CSS controls the presentation of it.
- Style sheets are a collection of formatting rules
- Styles are most commonly contained in external files
- Styles are applied to pages in the order they are found, cascading down from external to local styles
Websites are controlled and constructed by 5 main elements:
- HTML – documents structure
- CSS – documents look and feel
- PHP – documents processing and business logic
- mySQL – documents database to store content
When you write CSS, one of the things you’re actually doing is overriding those default browser styles, and replacing them with how you want the page to look.