body {
  background: #1e272e;
  color: #fff;
  font-family: 'Segoe UI', sans-serif;
  text-align: center;
  padding: 30px;
}
h1 {
  font-size: 3rem;
  margin-bottom: 20px;
}
#slot-display {
  display: grid;
  grid-template-columns: repeat(3, 80px);
  gap: 10px;
  justify-content: center;
  margin: 20px 0;
  font-size: 2rem;
}
.slot {
  width: 80px;
  height: 80px;
  background-color: #2f3640;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.5rem;
}
input, button, select {
  padding: 10px;
  margin: 10px;
  font-size: 1rem;
  border-radius: 5px;
  border: none;
}
button {
  background: #00a8ff;
  color: #fff;
  cursor: pointer;
}
#result, #balance {
  margin-top: 20px;
  font-size: 1.2rem;
}
#warning {
  color: #ff4757;
  font-weight: bold;
  margin-top: 20px;
}