body {
  margin: 0;
  background: linear-gradient(to right, #e0eafc, #cfdef3);
  font-family: 'Segoe UI', sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}

.calculator {
  background-color: #1e1e2f;
  padding: 25px;
  border-radius: 20px;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.3);
  width: 320px;
}

.display {
  width: 100%;
  height: 50px;
  font-size: 24px;
  text-align: right;
  padding: 10px;
  margin-bottom: 15px;
  border: none;
  border-radius: 10px;
  background: #fff;
  color: #333;
}

.buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
}

button {
  padding: 15px;
  font-size: 18px;
  background-color: #3b3e5c;
  color: #fff;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  transition: 0.2s;
}

button:hover {
  background-color: #5c5f7a;
}

.equal {
  background-color: #28a745;
  grid-column: span 2;
}

.equal:hover {
  background-color: #218838;
}

.zero {
  grid-column: span 2;
}

button[data-func] {
  background-color: #6c63ff;
}

button[data-func]:hover {
  background-color: #594fd1;
}