Before exploring some of what CSS3 has to offer, to prevent confusion, let's establish the terminology we use to describe a CSS rule. Consider the following example:
.round { /* selector */
border-radius: 10px; /* declaration */
}This rule is made up of the selector (.round) and then the declaration (border-radius: 10px;). The declaration is further defined by the property (border-radius:) and the value (10px;). Happy we're on the same page? Great, let's press on.
Note
Remember to check support for your users
As we delve into CSS3 more and more, don't forget to visit http://caniuse.com/, if you ever want to know what the current level of browser support is available for a particular CSS3 or HTML5 feature. Alongside showing browser version support (searchable by feature), it also provides the most recent set of global usage statistics from http://gs.statcounter.com/.