body{
  margin: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  font-family: sans-serif;
  }

.calculator {
  width: 300px;
  background-color: #333;
  padding: 20px;
  border-radius: 10px;
}

#display {
  width: 100%;
  height: 50px;
  font-size: 24px;
  text-align: right;
  margin-bottom: 10px;
  background: Black;
  color: Lime;
  font-family: sans-serif;
}

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

button {
  height: 50px;
  font-size: 18px;
  cursor: pointer;
  border-radius: 5px;
  border: none;
  font-family: sans-serif;
}

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