Information Technology Reference
In-Depth Information
14
A word processing template is really just a list of names for groups of formatting options applied in
a particular circumstance. When you have a list of things to which you want to apply bullets, a style
can specify any or all of these, and perhaps many more:
•
What the bullet should look like
•
How big the bullet (and its accompanying text) should be
•
The amount of space between the margin and the bullet
•
The amount of space between the bullet and the list text
•
The amount of space between items in the list
The same is true for a web document. What CSS does espe-
cially well is allow you to define what some text (or nontext
area on a page) is (there's that Semantic Web again), and apply
particular formatting to all other items on a page—or any other
page linked to the style sheet.
In the early days of the Web, site designers had to invent their
own navigational tools to allow visitors to roam around the
site's content. Although you could just have a set of text links,
that got old pretty quickly. People want menus, or something
that looks like a menu. Menus imply choices, of course, and you
always want an easy way to get back home, too. (Not to start a
Beatles sing-along here.)
When designers started creating navigation tools, those tools
had to be manually copied to every page on a site. If you wanted to give visitors a visual clue where
they were, you had to code that information on a page, with JavaScript or some HTML tag. This
was very tedious work, as you can imagine.
note
WordPress themes also have tem-
plate files that describe the look
of the four main areas of your
pages—header, footer, index, and
sidebar. These are different from
a word processing document tem-
plate in that the latter is mostly
focused on text formatting,
whereas WordPress templates
cover many other aspects of how
your page displays.
CSS Levels: A Brief History
As you study CSS, you'll discover two levels, or versions, of the standard. CSS Level 1 (CSS1)
became a W3C recommendation in 1996. It covers the basic text and layout functions, such as
fonts, general text alignment, background colors, and margins.
CSS Level 2 (CSS2) was adopted 2 years later (lightning speed for the W3C), with an update to 2.1
currently nearing the end of the W3C adoption cycle. (Yes, that's right, more than 10 years later,
which is more typical speed for the W3C.) CSS2 adds new capabilities like absolute, relative, and
fixed positioning of elements, the concept of media types, support for text that can be read right-
to-left, and new font properties such as shadows. V2.1 updates the standard to remove features
not supported by the current generation of browsers, and confirms some features that browsers
do support.
CSS Level 3 (CSS3) is in the very early stages of adoption, and is not yet substantially supported
by current browsers. You can follow this standard's progress at the W3C progress report page at
www.w3.org/Style/CSS/current-work#table.