body {
  text-align: center;
  background-color: #2c3e50;
  font-family: 'Press Start 2P', cursive;
}

#level-title {
  font-size: 3rem;
  margin:  5%;
  color: #ecf0f1;
}

.container {
  display: block;
  width: 80%;
  margin: auto;

}

.btn {
  margin: 20px;
  display: inline-block;
  height: 100px;
  width: 100px;
  border: 10px solid #34495e;
  border-radius: 20%;
  text-transform: uppercase;
  font-size: 50px;
  line-height: 2;
  text-emphasis: center;
  font-weight: bold;
  color: #34495e;
  cursor: pointer;
}

.game-over {
  background-color: #e74c3c;
  opacity: 0.8;
}

.red {
  background-color: #c0392b;
}

.green {
  background-color: #27ae60;
}

.blue {
  background-color: #2980b9;
}

.yellow {
  background-color: #f39c12;
}

.pressed {
  box-shadow: 0 0 20px white;
  background-color: grey;
}