For those frustrated with the limited control over document presentation provided by straight HTML markup, Cascading Style Sheets (CSS) are a welcome advance in web design. They are also the official W3C standard for controlling all presentation, leaving HTML markup to indicate structure as it was designed to do.
Like their counterparts in desktop publishing page-layout programs, style sheets in HTML allow authors to apply typographic styles and spacing instructions for elements on a page. The word cascading refers to what happens when several sources of style information vie for control of the elements on a page—style information is passed down from higher-level style sheets (and from parent to child element within a document) until it is overridden by a style command with more weight. (The cascading rules are discussed in detail later in this chapter.)
This comes as good news both for designers who want more control over presentation and for HTML purists who stand by the principle that style should be separate from content and structure. Style sheets make both these dreams possible, but it is important to be aware of their advantages and disadvantages.
Style sheets offer the following advantages to web designers:
Greater typography and page layout controls. With style sheets, you can specify traditional typography attributes such as font size, line spacing, and letter spacing. Style sheets also offer methods for ...