[Mirrored from: http://www.sgmlopen.org/sgml/docs/slide027.htm] -- See the entire document on the SGML Open server

The problem with CSS

CSS is appropriately designed for attaching simple formatting attributes to isolated HTML tags. But it is inherently incapable of handling generic SGML applications like the two just shown.

• CSS lacks the concept of a parse tree and therefore cannot address the SGML document structure. In particular:
  • It cannot grab an item (such as a chapter title) from one place and use it again in another place (such as a page header).
  • Aside from the degenerate case of being able to recognize the first letter of a line or the first line of a paragraph, it has no concept of sibling relationships. For example, it is impossible to write a CSS stylesheet that will render every other paragraph in bold, or autonumber the chapters in a book.
• CSS may allow one level of context specification (this is still under discussion). The formatting of generic SGML documents typically requires the ability to specify context at any level (for example, generating figure numbers differently depending on whether they are in a chapter or an appendix).
• CSS is not a programming language; it does not support decision structures and cannot be extended by the stylesheet designer.
• CSS cannot calculate quantities or store variables. This means, at the very least, that it cannot store commonly used parameters in one location that is easy to update.
• CSS cannot generate text (page numbers, etc.)
• CSS uses a simple box-oriented formatting model that works for current Web browsers but will not extend to more advanced applications of the markup, such as the generation of printed pages.
• CSS is oriented toward Western languages and assumes a horizontal left-to-right writing direction.