.game-container {
  text-align: center;
  margin-top: 100px;
}

.panel {
  display: grid;
  grid-template-columns: repeat(2, 100px);
  grid-template-rows: repeat(2, 100px);
  grid-gap: 10px;
  margin-bottom: 20px;
}

.button {
  width: 100px;
  height: 100px;
  cursor: pointer;
  border-radius: 50%;
  border: 2px solid black;
}

.green {
  background-color: green;
}

.red {
  background-color: red;
}

.yellow {
  background-color: yellow;
}

.blue {
  background-color: blue;
}