body {
    font-family: 'Roboto', sans-serif;
    background: linear-gradient(to right, #6a11cb, lightpink);
    height: 100vh;
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    color: #ffffff;
  }
  
  .calculator {
    width: 350px;
    background: #ffffff;
    padding: 20px;
    border-radius: 15px;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.3);
  }
  
  .display-container {
    margin-bottom: 15px;
  }
  
  #display {
    width: 100%;
    height: 60px;
    font-size: 2rem;
    text-align: right;
    padding: 10px;
    border: none;
    border-radius: 10px;
    background-color: #f4f6fc;
    box-shadow: inset 0 2px 5px rgba(0, 0, 0, 0.1);
    color: #333333;
  }
  
  .buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
  }
  
  .btn {
    height: 60px;
    font-size: 1.5rem;
    border: none;
    border-radius: 10px;
    background: #e4e6ef;
    color: #333333;
    cursor: pointer;
    transition: all 0.2s;
    box-shadow: 0 5px 10px rgba(0, 0, 0, 0.2);
  }
  
  .btn:hover {
    background: #d1d5df;
    transform: scale(1.05);
  }
  
  .operator {
    background: #6a11cb;
    color: #ffffff;
  }
  
  .operator:hover {
    background: #4f0bb3;
  }
  
  .clear {
    background: #f44336;
    color: #ffffff;
  }
  
  .clear:hover {
    background: #d32f2f;
  }
  
  .equal {
    background: #4caf50;
    color: #ffffff;
    grid-column: span 2;
  }
  
  .equal:hover {
    background: #388e3c;
  }