HTML and CSS Reference
Let's look at a brief roundup of the major CSS3 modules you'll be utilising and their
main features. You can find more details on the latest status of each module at the
W3C CSS Current Work page at www.w3.org/Style/CSS/current-work.en.html. As
you'll see, many of the modules are not yet finished, but this shouldn't stop you from
using some of those features. Many such features are already supported in brows-
ers, albeit with vendor prefixes (see the section ”Vendor Prefixes” for more details).
The major CSS3 modules featured in this topic include:
CSS Color ( www.w3.org/TR/css3-color). CSS Color defines the many ways
to specify color in CSS3, including RGB (red, green, blue), HSL (hue, satu-
ration, lightness), RGBA and HSLA (same as before but includes an alpha
channel to specify transparency), and a separate opacity property to apply
transparency to a whole selection of elements.
CSS Fonts Level 3 ( www.w3.org/TR/css3-fonts). As well as containing the
definitions for downloadable web fonts (previously in a separate module
known as, you guessed it, CSS web fonts), this module also contains defini-
tions for other font-affecting properties, such as font-feature-settings .
I won't talk about many of these beyond web fonts, because many do not
have much browser support yet. You'll mostly meet these in Chapter 3.
CSS Text Level 3 (www.w3.org/TR/css3-text). This goes hand in hand with
CSS Fonts Level 3 to give you more power over your words! As well as hous-
ing familiar items from CSS2, such as letter-spacing and text-transform ,
CSS Text introduces new friends, such as hyphenation and text shadow.
Selectors Level 3 ( www.w3.org/TR/css3-selectors). Selectors Level 3 defines
a much more powerful, robust set of mechanisms for selecting the elements
you want to apply styles to than was available in CSS2. Pretty much all of
these selectors have good support across modern browsers. These are dis-
cussed later in the “CSS3 Selectors” section of this chapter.
Media Queries ( www.w3.org/TR/css3-mediaqueries). The primary means by
which you can now serve optimized different layouts of the same content to
widely differing browsing devices—for example, wide screen and narrow
screen. You'll mostly meet these in Chapter 8.