 font-size: 10px;
  /* stacking  of outlines is undefined, so we cannot reliably to have an outline hide another outline.
   We are using a border instead,
   but still need to create an (invisible) outline to make sure that outline-offset does not compute to 0. */
  outline: solid 5px transparent;
  outline-offset: 1em;
  padding: 10px;
  border: solid 5px red;
  margin-left: -15px;
  margin-top: -15px;
}
div > div {
  width: 100px;
  height: 100px;
  background: green;
  outline: solid 5px white;
  font-s