| Each style rule in a style sheet has two main parts: the selector, which determines which elements are affected and the declaration, made up of one or more property/value pairs, which specifies just what should be done (Figures 7.1 and 7.2). Figure 7.1. A style rule is made up of a selector (which indicates which elements will be formatted), and a declaration (which describes the formatting that should be executed). Figure 7.2. Multiple property/value pairs in the declaration must be separated by a semicolon. Some folks simply end every property/value pair with a semicolonincluding the last pair in a listso that they never forget to add it. That's fine, as shown here, but not required. Note the extra spacing and indenting to keep everything readable. To construct a style rule: 1. | Type selector, where selector identifies the elements you wish to format. You'll learn how to create all sorts of selectors in Chapter 9, Defining Selectors. | 2. | Type { (an opening curly bracket) to begin the declaration. | 3. | Type property: value;, where property is the name of the CSS property that describes the sort of formatting you'd like to apply and value is one of a list of allowable options for that property. CSS properties and their values are described in detail in Chapters 1014. | 4. | Repeat step 3 as needed. | 5. | Type } to complete the declaration and the style rule. |
Tips You may add extra spaces, tabs, or returns between the steps above as desired to keep the style sheet readable (Figure 7.2). While each property/value pair should be separated from the next by a semicolon, you may omit the semicolon that follows the last pair in the list. Still, it's easier to always use it than to remember when it's possible to omit it. Missing (or duplicate) semicolons can make the browser completely ignore the style rule.
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