From http://www.w3schools.com (Copyright Refsnes Data)

CSS :first-line pseudo-element

Definition

The :first-line pseudo-element adds a special style to the first line of a text.

Examples

The "first-line" pseudo-element is used to add special styles to the first line of the text in a selector:

p {font-size: 12pt}
p:first-line {color: #FF0000;font-variant:small-caps}

<p>Some text that ends up on two or more lines</p>

The output could be something like this:

Some text that ends
up on two or more lines

In the example above the browser displays the first line formatted according to the "first-line" pseudo element. Where the browser breaks the line depends on the size of the browser window.

Note: The "first-line" pseudo-element can only be used with block-level elements.

Note: The following properties apply to the "first-line" pseudo-element:

font properties
color properties
background properties
word-spacing
letter-spacing
text-decoration
vertical-align
text-transform
line-height
clear

Pseudo-elements can also be combined with CSS classes:

p.article:first-line {color: #FF0000}

<p class="article">A paragraph in an article</p>

The example above will set the first line of all paragraphs with class="article" to red.

Try-It-Yourself Demos

Make the first line special
This example demonstrates how to add a special effect to the first line of a text.

Make the first letter and first line special
This example demonstrates how to add a special effect to the first letter and the first line of a text.

Complete CSS Reference