AWell, the short answer is that IE9 or older are not modern browsers and don't support many functions. The simple shadow that you see rendered is to hide a lot of the visual bugs around the text edges, but there are some that can't be overcome. If you are seeing a lot of bugs around the text edges, try increasing the depth a few pixels at a time. If you are seeing a line along the bottom of the stack, try adding bottom padding 10px at a time to the stack. Note: the demo has a line of red demo text and hasn't been accounted for, so you will probably see a line (render bug) below the text.