1. Definition and Usage of the .class selector select elements with a specific class attribute
2. To select elements with a specific class, start with a period (.) character, followed by the class name
3. You can also specify that only specific HTML elements should be affected by a given class. To implement this, start with the element name for example p, then write the period (.) character, followed by the class name (look at Example 1 below)
4. HTML elements can also refer to more than one class (look at Example 2 below)

CSS Syntax
.class {
 css declarations;
}

More Examples
Example 1
Style all <p> elements with class="slightbook":

p.slightbook {
 background-color: yellow;
}

Example 2
This <p> element will be styled according to class="slight" AND to class="book":

<p class="slight book">This paragraph refers to two classes.</p>

Example
Select and style all elements with class="slightbook":

.slightbook {
 background-color: red;
}