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