body {
      font-family: Arial, sans-serif;
      background-color: black;
      display: flex;
      justify-content: center;
      align-items: center;
      height: 100vh;
      margin: 0;
    }
      
    
    .calculator {
      background: #fff;
      padding: 40px;
      border-radius: 20px;
      box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
      width: 300px;
    }

    .display {
      color: #0056b3;
      width: 100%;
      height: 50px;
      margin-bottom: 20px;
      border: 0.5px solid #ccc;
      border-radius: 5px;
      text-align: right;
      padding: 10px;
      font-size: 2.5em;
    }

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

    .button {
      height: 50px;
      background-color: #007BFF;
      color: white;
      border: none;
      border-radius: 5px;
      font-size: 2em;
      cursor: pointer;
      transition: background-color 0.2s;
    }

    .button:hover {
      background-color: #0056b3;
    }

    .button:active {
      background-color: #004494;
    }

    .button.clear {
      background-color: #dc3545;
    }

    .button.clear:hover {
      background-color: #a71d2a;
    }

    .button.equals {
      background-color: #28a745;
      grid-column: span 2;
    }

    .button.equals:hover {
      background-color: #19692c;
    }