body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background-color: #f0f0f0;
  }
  
  .calculator-container {
    text-align: center;
  }
  
  .title {
    font-size: 50px;
    margin-bottom: 20px;
    font-family: "Arial", sans-serif;
    color: #333;
  }
  
  .calculator {
    border: 2px solid #ccc;
    padding: 25px;
    border-radius: 10px;
    background-color: #f9f9f9;
    box-shadow: 0px 4px 8px rgba(0, 0, 0, 0.1);
    width: 520px;
  }
  
  #result {
    width: 93%;
    padding: 10px;
    margin-bottom: 10px;
    font-size: 24px;
    border: none;
    border-radius: 5px;
    background-color: #fff;
    box-shadow: 0px 2px 4px rgba(0, 0, 0, 0.1);
  }
  
  .buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-gap: 10px;
  }
  
  button {
    padding: 15px;
    font-size: 18px;
    border: none;
    border-radius: 5px;
    background-color: #eee;
    cursor: pointer;
    transition: background-color 0.2s ease-in-out;
  }
  
  button:hover {
    background-color: #ccc;
  }