Internal Style

This style is applicable to particular HTML page elements.

Pros:

Here styles are grouped and placed into HTML file itself.
Easy to maintain in one place.
System gives second preference to this type style.

Cons:

This style is only applicable to a specified page.
If other page needs same style then need to copy over there too.

Example:

<head>
    <style>
        body {
            width:800px;
            border:dotted;
        }
    </style>
</head>

Example: Apply styles to HTML elements using CSS internal style sheet.

                        
<!DOCTYPE html />
<html>
<head>
    <title> CSS Internal Style </title>
    <style>
        body {
            width:800px;
            border:dotted;
        }
        h1{
            text-align:center;
        }
        h2{
            background-color:green;
            color:white;
        }
        p{
            font-family:arial;
        }
    </style>

</head>
<body>
    <h1>CSS Styles</h1>
    <h2> Different ways to apply CSS styles</h2>
    <p> a)	Inline style </p>
    <p> b)	Internal style sheet</p>
    <p> c)	External style sheet </p>

</body>
</html>

Result:

In the above example,

CSS internal style sheet styles are applied to HTML elements.
All styles are created inside the STYLE element which is under HEADER element.