You can define style rules based on the class attribute of the elements. All the elements having that class will be formatted according to the defined rule.
.black { color: #808000; }
This rule renders the content in black for every element with class attribute set to black in our document. You can make it a bit more particular. For example:
h1.black { color: #808000; }
This rule renders the content in black for only <h1> elements with class attribute set to black.
You can apply more than one class selectors to given element. Consider the following example:
<p class = "center bold"> This para will be styled by the classes center and bold. </p>