Chrome and opera both have bug in the styling of radio inputs, so that the shadow appears around a square box, rather than the native element.
Firefox:
Chrome & Opera:
Does anyone know of a workaround for this, rather than just removing shadows for chrome & opera?
Wrap the radio element in a div, and set that div's overflow to hidden, and border-radius to 100px. Then set the radio input to display block, and no margin.