body {
  margin: 0;
  padding: 0;
  background-color: #1a1a1a;
  color: #ffffff;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}

.app {
  text-align: center;
  padding: 2rem;
  background: #2e2e2e;
  border-radius: 16px;
  box-shadow: 0 0 20px rgba(0, 255, 128, 0.2);
  width: 90%;
  max-width: 500px;
}

button {
  padding: 1rem 2rem;
  margin: 0.5rem;
  font-size: 1.2rem;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  background: #4caf50;
  color: white;
  transition: background 0.3s ease;
}

button:hover {
  background: #66bb6a;
}