If there is no ancestral element with a non static position set, it will base its position on body --> it's not really the body but the initial containing block as defined here: w3.org/TR/CSS21/visudet.html#conta... it's upper than the body (and the html) element.
Example: jsfiddle.net/c9hbam0d/1/ (see how the element is at the bottom of the screen and not the bottom of the body or the html).
If there is no ancestral element with a non static position set, it will base its position on body --> it's not really the body but the initial containing block as defined here: w3.org/TR/CSS21/visudet.html#conta... it's upper than the body (and the html) element.
Example: jsfiddle.net/c9hbam0d/1/ (see how the element is at the bottom of the screen and not the bottom of the body or the html).
ah yup, so it can go all the way up to document if body or html isn't positioned as well. 👍