CSS is a plain text file format used for formatting content on web pages. It is used by web pages to help keep information in the proper display format. CSS files can help define font, size, color, spacing, border and location of HTML information on a web page, and can also be used to create a continuous look throughout multiple pages of a website.
The purpose of CSS is to provide Web developers with a standard way to define, apply, and manage sets of style characteristics. CSS provides these capabilities through a technical model based on a hierarchical scope of effect, the separation of style from content, and a well-defined set of published standards.
This section touches on each of these three topics in turn, focusing on how CSS can help the Web developer create maintainable, reusable code.
The "cascading" in Cascading Style Sheets refers to how property values are applied in the context of the parent/child hierarchy of the Web document. Child elements either inherit or override property values bound to their parent elements.