HTML and CSS Reference
In-Depth Information
3
Cascading Style Sheets (CSS) is a major piece of the art of web pro-
gramming. It is the technology that gives a web page its distinctive
look and feel. In this chapter you will learn how to use CSS to modify
the layout and typography of a web page to create web pages with style.
A cascading style sheet is a set of statements that applies rules to the various
elements of a web page, specifying the layout, typography, and other proper-
ties that those elements should assume when displayed by web browsers or
by WYSIWYG editing sotware. We speak of these properties as being in the
presentation layer of the web page as distinct from the semantic description
provided by the HTML markup of the page's content. CSS allows us to create
web pages that are more visually striking. At the same time they are simpler,
easier to maintain, more accessible, and friendlier to search engine robots and
other user agents. hese entities are concerned more with the meaning and
relevance of content on the Web than with how a particular page looks. CSS
also lets you create a web page with diferent presentation rules depending on
the type of device, or medium, accessing the page, such as a text-to-speech
reader for the visually impaired.
he CSS statements associated with a web page can appear in one or more
places:
