body {
  text-align: center;
}

.btn {
  height: 200px;
  width: 200px;
  border-radius: 20%;
  border: 10px solid black;
  margin: 2rem;
}

.btn-container {
  display: flex;
  justify-content: center; 
}

.yellow {
  background-color: #f99b45;
}

.red {
  background-color: #d95980;
}

.green {
  background-color: #63aac0;
}

.purple {
  background-color: #819ff9;
}

.btn:hover {
  cursor: pointer;
  transform: scale(1.05);
  transition: all 0.3s ease-in-out;
}
  
.flash {
  background-color: yellow;
}

.userflash {
  opacity: 0.5;
}