<details>
  <summary>Shave and a haircut ...</summary>
  ... two bits! And we see no lingering outline on the summary above.
</details>

summary {
  color: #099;
  cursor: pointer;
  outline: 0;
}

/* ignore the rest */
body {
  background-color: #555;
  background-color: white;
  border: .5em solid #555;
  bottom: 0;
  font-family: sans-serif;
  font-size: 1.1em;
  left: 0;
  margin: 0;
  padding: 1em;
  position: absolute;
  right: 0;
  top: 0;
}