body {
    background-color: #f5f5f5;
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 20px;
}

.container {
    background-color: white;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

h1 {
    color: #333;
    text-align: center;
    margin-bottom: 30px;
}

label {
    display: block;
    margin-bottom: 10px;
    font-weight: bold;
    color: #555;
    font-size: 18px;
}

input[type="number"] {
    width: 100%;
    padding: 15px;
    border: 2px solid #ddd;
    border-radius: 5px;
    font-size: 18px;
    margin-bottom: 20px;
    box-sizing: border-box;
}

button {
    width: 100%;
    padding: 15px;
    background-color: #4CAF50;
    color: white;
    border: none;
    border-radius: 5px;
    font-size: 20px;
    cursor: pointer;
}

button:hover {
    background-color: #45a049;
}

#result {
    margin-top: 20px;
    padding: 15px;
    background-color: #e8f5e8;
    border: 2px solid #4CAF50;
    border-radius: 5px;
    font-size: 20px;
    text-align: center;
    display: none;
}