246996016-HTML5-Step-by-Step

Constructing Style Rules 87
ul {
list-style-type: square
}
ol {
list-style-type: lower-alpha
}
Now further suppose that you want these specifications to apply to all the bulleted and
numbered lists in all documents, in your entire Web site. You can create an external
cascading style sheet, and then refer to that style sheet in the section of each
document to which it should apply. For example, here’s the entire text of an external
cascading style sheet (a plain text file with a .css extension) that would apply the specified
rules.
ul {
}
ol {
}
list-style-type: square;
list-style-type: lower-alpha;
It’s the same code that was enclosed within the tag in the previous example.
When style rules appear in a separate file, you don’t need the tag.
A cascading style sheet can get very complex if it includes a lot of rules, but the principles
are always the same as in these examples. The remainder of this chapter explores how to
construct style rules within both embedded and external style sheets.
Constructing Style Rules
An embedded style sheet consists of a two-sided tag placed in the section
of a document. Between the and tags, you define the rules for the
various styles.
A style rule begins with the name of the tag or other element to which the style applies.
For example, if you are creating a rule that will apply to all instances of the tag,
start the rule with h1 (no brackets):
h1
No brackets are necessary around h1 because it’s already enclosed in the tag.