corner-radius attribute

Type:length, percentage (calculated with respect to the width of the block)
Used By:All block elements

For any block element, set the radius of the corners of the block. The default is 0, which results in a regular rectangular box, but for rounded corners it can be set to other non-zero values. If the specified value is a percentage, it's based on the width of the box, not it's height.

This value is inherited, so any blocks contained within a box with rounded corners will themselves have rounded corners.

Creates a box with the corners rounded by 20 points.

<box width="100" height="200" corner-radius="20%"/>