body {
  font-family: 'Segoe UI', sans-serif;
  text-align: center;
  background: radial-gradient(circle at top, #0a0a0a, #111);
  color: #00ffcc;
  margin: 0;
  padding-top: 40px;
}
h1 {
  color: #00ffee;
}
button {
  background: #00ffcc;
  color: #111;
  border: none;
  padding: 10px 25px;
  border-radius: 10px;
  cursor: pointer;
  font-size: 16px;
  transition: 0.2s;
}
button:hover {
  background: #00ffee;
  transform: scale(1.05);
}
.upgrades {
  margin-top: 30px;
}
.stats {
  font-size: 18px;
  margin-bottom: 15px;
}