.card {
  position: relative;
  isolation: isolate;
  display: grid;
  grid-template-rows: auto 1fr;
  grid-template-areas: "header" "body";
  padding: 2rem;
  border: 1px solid #888;
  width: min(100%, 40rem);
}

.card__header {
  grid-area: header;
  padding: 1rem;
}

.card__body {
  grid-area: body;
  padding: 1rem;
}

.card__bg {
  position: relative;
  grid-area: header;
  background-color: rebeccapurple;
  z-index: -1;
}