body {
  font-family: Arial, sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  margin: 0;
  background-color: #f4f4f9;
}

.calculator {
  border: 1px solid #ccc;
  border-radius: 10px;
  padding: 20px;
  background-color: #fff;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
  width: 300px;
}

.display {
  width: 100%;
  height: 50px;
  margin-bottom: 20px;
  text-align: right;
  font-size: 24px;
  padding: 5px;
  border: 1px solid #ddd;
  border-radius: 5px;
  background-color: #f9f9f9;
}

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

button {
  height: 50px;
  font-size: 18px;
  border: none;
  border-radius: 5px;
  cursor: pointer;
  background-color: #e0e0e0;
  transition: background-color 0.2s;
}

button:hover {
  background-color: #d0d0d0;
}

.operator {
  background-color: #ff9800;
  color: white;
}

.operator:hover {
  background-color: #e68a00;
}

.equals {
  background-color: #4caf50;
  color: white;
}

.equals:hover {
  background-color: #3e8e41;
}

.clear {
  background-color: #f44336;
  color: white;
}

.clear:hover {
  background-color: #d32f2f;
}