HTML and CSS Reference
Although each CSS level builds on its predecessor, where relevant, a level recommends a particular feature from its
predecessor no longer be used and thus deprecated. This means that when referring to CSS3, one is actually referring
to all the features made available throughout CSS, except those that have been deprecated.
In CSS3 Foundations , you learn CSS3, which includes not just the newest of features, but also those from the previ-
ous CSS levels that experienced designers and developers have relied on for years.
The Role of CSS
The main purpose of CSS is to separate structure (HTML) from presentation (CSS). Figure 1-1 shows a web page
that consists only of HTML, without any CSS.
Figure 1-1 A web page without any CSS.
Figure 1-2 shows the same web page with CSS applied to it—a huge difference, one that makes the page much more
In the early days of styling web pages, structure and presentation were mixed together. Presentation was directly ap-
plied to structure, meaning that maintaining pages became an arduous task. If, for example, somebody decided that