HTML, the primary language of the Web, is a subset of SGML, one of the pioneering structured document formats. The goals of SGML and its offspring HTML are to encode a document's logical structure, not its presentation or final appearance (Lie & Saarela 96).
But designers have found ways to bend and shape the original HTML specification to their needs to control the appearance of Web pages. This has resulted in documents weighed down by heavy use of tables and tags. Not only does such coding practice stray from the intent of HTML, it slows page-loading times.
One of the goals of the original CSS1 specification as adopted in 1996 was to restore the separation of a document's logical structure and its physical presentation. Style sheets allow designers to create lean HTML pages that outline the top-level semantics with heading, paragraph and division tags, and leave the details of font styles, text and background colors in a style sheet.
"Cascading style sheets enable us to get more control the right way: by separating the part that defines structure from the part that defines form. The HTML remains clean and simple, as originally intended, and the CSS code controls appearances from afar" (Mulder).
To be true to this intent, Nielsen argues for the use of linked style sheets instead of embedded styles because they allow designers to alter the appearance of an entire site by changing just one document, and minimize page sizes.
"If you use a single style sheet for your entire site, that file will be a single download once and for all" (Nielsen 81).
Such practical considerations, along with greater control over layout and presentation, may sell more designers on using style sheets. But the idea of dividing style and structure is more than an abstract and grandiose goal. By keeping complex presentation rules separate from the HTML document, style sheets help make documents simpler and easier to manipulate, which in turn helps uphold the goal of platform independence.
Abstract, 1, 2, 3, 4, 5, 6, Works cited
