The margin-left: auto; margin-right: auto way to horizontally center something works well when the container is static or relative positioned but seems to fail when it is absolute positioned.
Is there a way to get the auto margins to work in this situation? I need the container to be absolute for certain reasons.
absolute positioning is, by definition, going to use 0,0 as a point of reference for your positioning.
What I would suggest is using a container with position:absolute and width 100%, and then specifying with a position: 0 auto anything you want centered.