body {
  font-family: Arial, sans-serif;
  background-color: #f4f4f4;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  margin: 0;
}

.calculator {
  background-color: #fff;
  border-radius: 10px;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
  padding: 20px;
  width: 300px;
}

#display {
  width: 100%;
  height: 50px;
  margin-bottom: 10px;
  font-size: 1.5rem;
  text-align: right;
  border: none;
  outline: none;
  padding: 10px;
  background-color: #f4f4f4;
  border-radius: 5px;
}

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

button {
  height: 50px;
  font-size: 1.2rem;
  border: none;
  outline: none;
  border-radius: 5px;
  cursor: pointer;
  background-color: #e0e0e0;
  transition: background-color 0.2s ease-in-out;
}

button:hover {
  background-color: #d6d6d6;
}

.equal {
  grid-column: span 4;
  background-color: #ff9500;
  color: #fff;
}

.equal:hover {
  background-color: #e08600;
}