#calculator {
            max-width: 400px;
            margin: 0 auto;
            padding: 20px;
            background-color: #ffffff;
            border-radius: 8px;
            box-shadow: 0 0 15px rgba(0, 0, 0, 0.1);
        }
        input {
           width: calc(100% - 20px);
    padding: 15px;
    margin-bottom: 15px;
    box-sizing: border-box;
    border: 1px solid #ddd;
    border-radius: 4px;
    outline: none;
    text-align: center;
        }
        button {
            background-color: #4caf50;
    color: white;
    padding: 10px 15px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 19px;
        }
        button:hover {
            background-color: #45a049;
        }
        h2, h3 {
            color: #333;
        }
        h2 {
            margin-bottom: 20px;
        }
        h3 {
            margin-top: 20px;
            font-size: 21px;
    color: #4caf50;
    font-weight: bold;
    margin-top: 20px;
    border: 1px solid #ccc;
    border-radius: 4px;
    padding: 15px;
    background-color: #eee;
        }
        #result {
            font-size: 24px;
            color: #4caf50;
        }
        
       label {
            display: block;
    margin: 5px 0 5px;
    text-align: center;
    }
    nrr {
     color: red;
    }