body {
  margin: 0;
  font-family: Arial;
  background: linear-gradient(135deg, #111, #1a1a1a);
  color: white;
  text-align: center;
}

.app {
  padding: 30px;
}

h1 {
  margin-bottom: 40px;
}

.screen {
  display: none;
}

.screen.active {
  display: block;
  animation: fade 0.5s ease;
}

button {
  padding: 15px 25px;
  border: none;
  border-radius: 12px;
  background: crimson;
  color: white;
  font-size: 16px;
  margin: 15px;
  cursor: pointer;
  transition: 0.3s;
}

button:hover {
  background: darkred;
}

select {
  padding: 10px;
  border-radius: 8px;
  margin: 15px;
}

@keyframes fade {
  from {opacity:0;}
  to {opacity:1;}
}