The right property for a positioned element specifies the distance from the right edge of the parent element, excluding padding, margin, and border width, to the right edge of the child element.
The coordinate count depends on the value of the position property. If it is absolute, the parent is the browser window and the element is positioned from its right edge. If the value is relative, right is measured from the right edge of the element's original position.
right: auto | length | percentage;