body {
  margin: 0;
  height: 100vh;
  background: linear-gradient(to bottom right, #e6e6fa, #d8bfd8);
  display: flex;
  justify-content: center;
  align-items: center;
  font-family: 'Segoe UI', sans-serif;
}

.calculator {
  background-color: #f5f0ff;
  padding: 2rem;
  border-radius: 20px;
  box-shadow: 0 10px 25px rgba(150, 120, 180, 0.2);
  width: 320px;
}

#display {
  width: 100%;
  height: 50px;
  font-size: 1.5rem;
  margin-bottom: 1rem;
  padding: 10px;
  border-radius: 10px;
  border: none;
  text-align: right;
  background-color: #f0eaff;
  color: #4b0082;
}

.buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
}

button {
  padding: 20px;
  font-size: 1.2rem;
  background-color: #e0c7ff;
  border: none;
  border-radius: 12px;
  color: #4b0082;
  transition: 0.2s ease-in-out;
  cursor: pointer;
}

button:hover {
  background-color: #d1b3ff;
}

button.zero {
  grid-column: span 2;
}