[JSWolf]

I use a 2px 20% wide line to mark a scene break. It looks quite good.

hr {
  margin-top: 0.9em;
  margin-right: 40%;
  margin-bottom: 0.9em;
  margin-left: 40%;
  border-top: 2px solid;
}
hr + p {
  text-indent: 0;
}