The CSS3 @font-face Rule

Before CSS3, web designers had to use fonts that were already installed on the user's computer.
With CSS3, web designers can use whatever font he/she likes.
When you have found/bought the font you wish to use, include the font file on your web server, and it will be automatically downloaded to the user when needed.
Your "own" fonts are defined in the CSS3 @font-face rule.

Browser Support

Firefox, Chrome, Safari, and Opera support fonts of type .ttf (True Type Fonts) and .otf (OpenType Fonts).
Internet Explorer 9+ supports the new @font-face rule, but it only supports fonts of type .eot (Embedded OpenType).
Note: Internet Explorer 8 and earlier versions, do not support the new @font-face rule.

Using The Font You Want

In the new @font-face rule you must first define a name for the font (e.g. myFirstFont), and then point to the font file.
To use the font for an HTML element, refer to the name of the font (myFirstFont) through the font-family property:

Example 
<style>
@font-face
{
font-family: myFirstFont;
src: url('Sansation_Light.ttf'),
     url('Sansation_Light.eot'); /* IE9+ */
}

div
{
font-family:myFirstFont;
}
</style> 

Using Bold Text

You must add another @font-face rule containing descriptors for bold text:

Example
@font-face
{
font-family: myFirstFont;
src: url('Sansation_Bold.ttf'),
     url('Sansation_Bold.eot'); /* IE9+ */
font-weight:bold;
}

The file "Sansation_Bold.ttf" is another font file, that contains the bold characters for the Sansation font.
Browsers will use this whenever a piece of text with the font-family "myFirstFont" should render as bold.
This way you can have many @font-face rules for the same font.

CSS3 Font Descriptors

The following table lists all the font descriptors that can be defined inside the @font-face rule: