The attribute in CSS3 enables developers to give their elements smooth, rounded edges. This is readily adaptable to cover any angle on either side.  Border-bottom-right-radius, border-bottom-left-radius, border-top-right-radius, and border-top-left-radius allow us to choose individual values for every one of the four corners. Alternatively, we may make each corner elliptical by giving it a number for two different radii (arc-shaped).