body {
  display: flex;
  flex-wrap: wrap;
  gap: 2rem;
}

.parent {
  border: black solid 3px;
  width: 20vw;
  aspect-ratio: 1;

  div {
    border: red solid 2px;
    width: 5vw;
    aspect-ratio: 1;
    background-color: red;
    border-radius: 50%;
  }
}

.flex {
  display: flex;
  align-items: center;
  justify-content: center;
}

.grid {
  display: grid;
  place-items: center;
}

.margin {
  display: flex;

  div {
    margin: auto;
  }
}

.position {
  position: relative;

  div {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
  }
}