Thanks Unsubscribe I found the answer. In IE10, "border-radius" doesn't work for me. To make it work, you must specify each corner:
border-top-left-radius:5px; border-top-right-radius:5px; border-bottom-left-radius:5px; border-bottom-right-radius:5px;
Indeed, the site you submitted does just that (see page source). It gives instructions as output:
border-radius: 5px;
but internally it declares 4 corners separately, as indicated above.
This was extracted from the question and sent to OP.
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