body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: #f1f1f1;
  }
  
  .calculator {
    width: 400px;
    height: 500px;
    background-color: white;
    box-shadow: 0px 0px 10px rgba(0, 0, 0, 0.1);
    border-radius: 10px;
    display: flex;
    flex-direction: column;
    align-items: center;
  }
  
  .display {
    width: 100%;
    height: 200px;
    background-color: #ddd;
    font-size: 48px;
    text-align: right;
    padding: 20px;
    box-sizing: border-box;
  }
  
  .buttons {
    width: 100%;
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-gap: 20px;
    padding: 20px;
    box-sizing: border-box;
  }
  
  button {
    width: 100%;
    height: 70px;
    background-color: white;
    border: 1px solid #ddd;
    font-size: 24px;
    border-radius: 10px;
    cursor: pointer;
  }
  
  button.operator {
    background-color: #f1c40f;
}

button:active {
transform: scale(0.95);
}