CSS is a special style sheet language basically beneficial for describing the lookout and the basic structure of a document written in a markup language. CSS means Cascading Style Sheets.
Although CSS is made to be as independent of the markup language of the documents to which it is set to, in brief honestly, it’s beneficial used with HTML and XML including XHTML.
CSS has a basic syntax and uses a number of keywords to identify the names of different style properties.
A style sheet has a list of rules. Each rule has one or multiple selectors, and a declaration block.