Opinion of one of the creators of CSS

Håkon Lie, who once created CSS with Bert Bos, now runs CTO on Opera Software.
In a recent article for CNET, Håkon addressed the situation with two formats for office documents: OpenDocument format (ODF) and Office Open XML (developed in the bowels of Microsoft). Sequentially examining the situation, Håkon notes that he does not like both specifications: neither 700 pages of ODF, nor 6,000 pages of OOXML. There is another way of development:
It is possible to create a new format on top of the widely implemented HTML and CSS. Additional semantics (for example, formulas) can be placed inside attributes as is done in microformats . CSS 3 allows you to implement new features (e.g., callouts , footers ).
and further:
In order to show that this is possible, I and Bert Bos published a book written in HTML and CSS . A significant feature of this approach is the fact that documents can be viewed in most browsers.
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