body {
    font-family: 'Arial', sans-serif;
    background: #f4f4f4;
    color: #333;
    text-align: center;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}

.container {
    background: #fff;
    padding: 40px;
    border-radius: 10px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
    width: 480px;
    display: flex;
    flex-direction: column;
    align-items: center;
}

h1 {
    font-size: 32px;
    margin-bottom: 20px;
}

label {
    font-size: 20px;
    margin-top: 15px;
}

input[type="number"] {
    font-size: 20px;
    padding: 10px;
    margin: 10px 0;
    border-radius: 5px;
    border: 1px solid #ccc;
    width: 100%;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    background: #f9f9f9;
    transition: border-color 0.3s;
}

input[type="number"]:focus {
    border-color: #007bff;
    outline: none;
}

#number-display {
    font-size: 28px;
    font-weight: bold;
    margin: 20px 0;
    color: #007bff;
}

button {
    background: #007bff;
    color: white;
    border: none;
    padding: 15px 20px;
    font-size: 22px;
    border-radius: 5px;
    cursor: pointer;
    transition: background 0.3s;
    margin-top: 15px;
}

button:hover {
    background: #0056b3;
}