Grid

/*CSS related to the topic*/
.container {
  display: grid;
  grid-template-columns: 100px 100px 100px;
  grid-auto-rows: 100px;
}
/*Additional CSS for styling*/
.item1 {
  background-color: #5bc292;
}
.container > div {
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 24px;
  color: #00000;
  border: 1px solid #5bc292;
}