index.css

.button {
  position: absolute;
  top: 2rem;
  left: 1rem;
  width: 180px;
  padding: 1rem;
  background-color: palevioletred;
  color: white;
  font-size: 1rem;
  font-weight: 700;
  font-family: Arial;
}

.button:hover {
  cursor: pointer;
  background-color: goldenrod;
}

.header {
  color: #333;
  font-family: monospace;
  font-size: 2rem;
  text-transform: uppercase;
  text-align: center;
}

.wrapper {
  display: flex;
  justify-content: center;
  align-items: center;
  height: calc(100vh - 8rem);
  width: 100vw;
}

.container {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  margin: 1rem;
  padding: 0.25rem;
}

.child {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 480px;
  height: 480px;
  margin: 1rem;
  padding: 0.5rem;
  font-size: 1.5rem;
}

.one {
  background-color: peru;
}

.two {
  background-color: papayawhip;
}

.three {
  background-color: peachpuff;
}