CSS3 takes borders to a new level with the ability to use gradients, rounded corners, shadows and border images. Mozila, Firefox and Safari 3 have implemented this function, which allows you to create round corners on box-items.
Update: Now works in Internet Explorer from version 9.0

Example 1 - Rounded Borders

background-color: #DAE8EC;
border-radius: 10px;
-moz-border-radius: 10px;
-webkit-border-radius: 10px;
border: 2px solid #B8CB99;
padding: 10px;

Example

This is an example of a box with rounded corners. This example will currently work in Mozilla, Firefox and Safari browsers.

Example 2 - Rounded Borders (Specific Corners)

background-color: #DAE8EC;
border-top-left-radius: 10px;
border-bottom-right-radius: 10px;
-moz-border-radius-topleft: 10px;
-webkit-border-top-left-radius: 10px;
-moz-border-radius-bottomright: 10px;
-webkit-border-bottom-right-radius: 10px;
border: 2px solid #B8CB99;
padding: 10px;

Example

This is an example of a box with rounded top left and bottom right corners. This example will currently work in Mozilla, Firefox and Safari browsers.


You can use the following properties for Mozilla-Firefox / Safari

top-left -moz-border-radius-topleft / -webkit-border-top-left-radius
top-right -moz-border-radius-topright / -webkit-border-top-right-radius
bottom-left -moz-border-radius-bottomleft / -webkit-border-bottom-left-radius
bottom-right -moz-border-radius-bottomright / -webkit-border-bottom-right-radius

Example 3 - Gradient Borders

border: 8px solid #000;
-moz-border-bottom-colors: #555 #666 #777 #888 #999 #aaa #bbb #ccc;
-moz-border-top-colors: #555 #666 #777 #888 #999 #aaa #bbb #ccc;
-moz-border-left-colors: #555 #666 #777 #888 #999 #aaa #bbb #ccc;
-moz-border-right-colors: #555 #666 #777 #888 #999 #aaa #bbb #ccc;
padding: 5px 5px 5px 15px;

Example

This is an example of a box with a gradient border. This example will currently work in Mozilla and Firefox browsers.