Property aspect-ratio

Specifies preferred aspect ratio of an element

/* The current way */
.card__thumb {
  position: relative;
  padding-top: 75%;
}

/* With native aspect-ratio support */
.card__thumb {
  position: relative;
  aspect-ratio: 4/3;
}

Responsive circles

.person {
  width: 180px;
  aspect-ratio: 1;
}