The CSS border-radius property defines the radius of an element's corners, This property allows you to add rounded corners to elements
The CSS3 border-radius property allows web developers to easily utilise rounder corners in their design elements, without the need for corner images or the use of multiple div tags, and is perhaps one of the most talked about aspects of CSS3.
Rounded corners for an element with a specified background color:
Rounded corners for an element with a border:
Rounded corners for an element with a background image: