*, *::before, *::after {
  box-sizing: border-box;
}

body {
  height: 100vh;
  margin: 0;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}

section {
  display: grid;
  grid-template-columns: repeat(7, 10vmin);
  grid-template-rows: repeat(6, 10vmin);
  grid-gap: 1vmin;
}

section div {
  border-radius: 50%;
  border: 1px solid grey;
}