div.af-gui-recaptcha2-placeholder {
  width: 305px;
  height: 76px;
  opacity: .85;
  background-image: url('rc2-light.png');
  background-size: contain;
  background-repeat: no-repeat;
  background-position: center;
}
div.af-gui-recaptcha2-placeholder.rc2dark {
  background-image: url('rc2-dark.png');
}